Steps to reproduce:
1) Import several puppet classes in context of OrgA
2) Delete one of them
3) Switch context to OrgB
4) Import puppet classes
5) observe the error

 | ActiveRecord::RecordInvalid (Validation failed: Name is already taken):
 |   app/services/puppet_class_importer.rb:333:in `find_or_create_env'
 |   app/services/puppet_class_importer.rb:256:in `add_classes_to_foreman'
 |   app/services/puppet_class_importer.rb:71:in `block in obsolete_and_new'
 |   app/services/puppet_class_importer.rb:69:in `each'
 |   app/services/puppet_class_importer.rb:69:in `obsolete_and_new'
 |   app/controllers/concerns/foreman/controller/environments.rb:41:in `obsolete_and_new'
 |   app/controllers/concerns/application_shared.rb:15:in `set_timezone'
 |   app/models/concerns/foreman/thread_session.rb:32:in `clear_thread'
 |   app/controllers/concerns/foreman/controller/topbar_sweeper.rb:12:in `set_topbar_sweeper_controller'
 |   /home/vagrant/projects/katello/lib/katello/params_parser_wrapper.rb:12:in `call'
 |   lib/middleware/catch_json_parse_errors.rb:8:in `call'
 |   lib/middleware/session_safe_logging.rb:17:in `call'
 |   lib/middleware/tagged_logging.rb:18:in `call'