When trying to use provisioning template preview, an exception is raised.
This happens regardless of the existence of a host.

Last upstream commit that I'm on: 74f5ebf

 | NoMethodError: undefined method `layout' for nil:NilClass
 | /home/ik/projects/foreman/app/models/host/managed.rb:319:in `diskLayout'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/safemode-1.3.4/lib/safemode/jail.rb:31:in `method_missing'
 | Kickstart default:194:in `bind'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/safemode-1.3.4/lib/safemode.rb:51:in `eval'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/safemode-1.3.4/lib/safemode.rb:51:in `eval'
 | /home/ik/projects/foreman/lib/foreman/renderer.rb:128:in `render_safe'
 | /home/ik/projects/foreman/lib/foreman/renderer.rb:246:in `unattended_render'
 | /home/ik/projects/foreman/app/controllers/templates_controller.rb:115:in `safe_render'
 | /home/ik/projects/foreman/app/controllers/templates_controller.rb:96:in `preview'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_controller/metal/basic_implicit_render.rb:4:in `send_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/abstract_controller/base.rb:186:in `process_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_controller/metal/rendering.rb:30:in `process_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/abstract_controller/callbacks.rb:20:in `block in process_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:108:in `block in run_callbacks'
 | /home/ik/projects/foreman/app/controllers/concerns/application_shared.rb:15:in `set_timezone'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /home/ik/projects/foreman/app/models/concerns/foreman/thread_session.rb:32:in `clear_thread'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /home/ik/projects/foreman/app/controllers/concerns/foreman/controller/topbar_sweeper.rb:12:in `set_topbar_sweeper_controller'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/audited-4.6.0/lib/audited/sweeper.rb:14:in `around'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/audited-4.6.0/lib/audited/sweeper.rb:14:in `around'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:135:in `run_callbacks'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/abstract_controller/callbacks.rb:19:in `process_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_controller/metal/rescue.rb:20:in `process_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/notifications.rb:166:in `block in instrument'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/notifications.rb:166:in `instrument'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_controller/metal/instrumentation.rb:30:in `process_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_controller/metal/params_wrapper.rb:252:in `process_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activerecord-5.1.4/lib/active_record/railties/controller_runtime.rb:22:in `process_action'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/abstract_controller/base.rb:124:in `process'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionview-5.1.4/lib/action_view/rendering.rb:30:in `process'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_controller/metal.rb:189:in `dispatch'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_controller/metal.rb:253:in `dispatch'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/routing/route_set.rb:49:in `dispatch'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/routing/route_set.rb:31:in `serve'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/journey/router.rb:50:in `block in serve'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/journey/router.rb:33:in `each'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/journey/router.rb:33:in `serve'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/routing/route_set.rb:834:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/apipie-rails-0.5.6/lib/apipie/static_dispatcher.rb:65:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/bullet-5.7.1/lib/bullet/rack.rb:12:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/apipie-rails-0.5.6/lib/apipie/extractor/recorder.rb:136:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/apipie-rails-0.5.6/lib/apipie/middleware/checksum_in_headers.rb:27:in `call'
 | /home/ik/projects/foreman/lib/middleware/catch_json_parse_errors.rb:8:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-openid-1.4.2/lib/rack/openid.rb:98:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/etag.rb:25:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/conditional_get.rb:38:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/head.rb:12:in `call'
 | /home/ik/projects/foreman/lib/middleware/session_safe_logging.rb:17:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/session/abstract/id.rb:232:in `context'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/session/abstract/id.rb:226:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/cookies.rb:613:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activerecord-5.1.4/lib/active_record/migration.rb:556:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/callbacks.rb:26:in `block in call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:97:in `run_callbacks'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/callbacks.rb:24:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/executor.rb:12:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/debug_exceptions.rb:59:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/show_exceptions.rb:31:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/railties-5.1.4/lib/rails/rack/logger.rb:36:in `call_app'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/railties-5.1.4/lib/rails/rack/logger.rb:26:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/sprockets-rails-3.2.1/lib/sprockets/rails/quiet_assets.rb:13:in `call'
 | /home/ik/projects/foreman/lib/middleware/tagged_logging.rb:18:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/remote_ip.rb:79:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/request_id.rb:25:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/method_override.rb:22:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/runtime.rb:22:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/activesupport-5.1.4/lib/active_support/cache/strategy/local_cache_middleware.rb:27:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/executor.rb:12:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/actionpack-5.1.4/lib/action_dispatch/middleware/static.rb:125:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/sendfile.rb:111:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/secure_headers-3.7.3/lib/secure_headers/middleware.rb:12:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/railties-5.1.4/lib/rails/engine.rb:522:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/railties-5.1.4/lib/rails/railtie.rb:185:in `public_send'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/railties-5.1.4/lib/rails/railtie.rb:185:in `method_missing'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/urlmap.rb:68:in `block in call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/urlmap.rb:53:in `each'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/urlmap.rb:53:in `call'
 | /home/ik/projects/foreman/lib/foreman/telemetry_rack.rb:9:in `call'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/rack-2.0.3/lib/rack/handler/webrick.rb:86:in `service'
 | /home/ik/.rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/webrick/httpserver.rb:140:in `service'
 | /home/ik/.rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/webrick/httpserver.rb:96:in `run'
 | /home/ik/.rvm/rubies/ruby-2.3.4/lib/ruby/2.3.0/webrick/server.rb:296:in `block in start_thread'
 | /home/ik/.rvm/gems/ruby-2.3.4/gems/logging-2.2.2/lib/logging/diagnostic_context.rb:474:in `block in create_with_logging_context'