How to reproduce:

1. install a plugin that uses deface (e.g. katello, foreman_remote_execution…)
2. use the web server or call `rake apipie:cache:index`

Results:

MD5 is used by deface with the following backtrace:

 | /opt/theforeman/tfm/root/usr/share/gems/gems/deface-1.2.0/lib/deface/action_view_extensions.rb:55:in `method_name'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/actionview-5.1.4/lib/action_view/template.rb:157:in `block in render'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/activesupport-5.1.4/lib/active_support/notifications.rb:168:in `instrument'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/actionview-5.1.4/lib/action_view/template.rb:352:in `instrument_render_template'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/actionview-5.1.4/lib/action_view/template.rb:155:in `render'
 | /opt/theforeman/tfm/root/usr/share/gems/gems/deface-1.2.0/lib/deface/action_view_extensions.rb:41:in `render'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/actionview-5.1.4/lib/action_view/renderer/template_renderer.rb:64:in `render_with_layout'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/actionview-5.1.4/lib/action_view/renderer/template_renderer.rb:50:in `render_template'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/actionview-5.1.4/lib/action_view/renderer/template_renderer.rb:14:in `render'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/actionview-5.1.4/lib/action_view/renderer/renderer.rb:42:in `render_template'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/actionview-5.1.4/lib/action_view/renderer/renderer.rb:23:in `render'
 | /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/actionview-5.1.4/lib/action_view/helpers/rendering_helper.rb:32:in `render'
 | /opt/theforeman/tfm/root/usr/share/gems/gems/apipie-rails-0.5.6/lib/tasks/apipie.rake:121:in `block in render_page'