Description of problem:

While performing uninstallation of the foreman templates plugin on the Satellite server, the foreman-rake command fails with the error:

Documentation followed:
https://access.redhat.com/documentation/en-us/red_hat_satellite/6.15/html/managing_hosts/synchronizing_templates_repositories_managing-hosts#Uninstalling_the_Foreman_Templates_plugin_managing-hosts

How reproducible:

 100%

Is this issue a regression from an earlier version:

  Red Hat Satellite 6.13, 6.14

Steps to Reproduce:

1. Access the CLI of the Satellite server, run the command to disable the plugin using the Satellite installer:

~~~
$ satellite-installer --no-enable-foreman-plugin-templates
~~~

2. Once the above command is completed, run the following command:

~~~
$ foreman-rake templates:cleanup
~~~

The above command fails with error.

===============================================
$ foreman-rake templates:cleanup --trace

• • Invoke templates:cleanup (first_time)
  • Invoke environment (first_time)
  • Execute environment
  • Execute templates:cleanup
    Cleaning data...
    rake aborted!
    NameError: uninitialized constant Setting::TemplateSync
    /usr/share/gems/gems/foreman_hooks-0.3.17/lib/foreman_hooks/as_dependencies_hook.rb:4:in `load_missing_constant'
    /usr/share/gems/gems/foreman_templates-9.4.0/app/services/foreman_templates/cleaner.rb:10:in `remove_settings'
    /usr/share/gems/gems/foreman_templates-9.4.0/app/services/foreman_templates/cleaner.rb:4:in `clean_up!'
    /usr/share/gems/gems/foreman_templates-9.4.0/lib/tasks/foreman_templates_tasks.rake:70:in `block (2 levels) in <top (required)>'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/task.rb:281:in `block in execute'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/task.rb:281:in `each'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/task.rb:281:in `execute'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/task.rb:219:in `block in invoke_with_call_chain'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/task.rb:199:in `synchronize'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/task.rb:199:in `invoke_with_call_chain'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/task.rb:188:in `invoke'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/application.rb:160:in `invoke_task'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/application.rb:116:in `block (2 levels) in top_level'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/application.rb:116:in `each'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/application.rb:116:in `block in top_level'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/application.rb:125:in `run_with_threads'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/application.rb:110:in `top_level'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/application.rb:83:in `block in run'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/application.rb:186:in `standard_exception_handling'
    /usr/share/gems/gems/rake-13.0.1/lib/rake/application.rb:80:in `run'
    /usr/share/gems/gems/rake-13.0.1/exe/rake:27:in `<top (required)>'
    /usr/bin/rake:23:in `load'
    /usr/bin/rake:23:in `<main>'
    Tasks: TOP => templates:cleanup
    ===============================================

Actual behavior:
While trying to uninstall the templates plugin on the Satellite server, the steps followed from the documentation failed with an error.

Expected behavior:
The command should run without any error, it should perform template cleanup on the Satellite server.