puppet classes removed from host
Description of problem:
Puppet classes are being removed from Hosts when working with non-admin user.
If I submit host information with a non-admin user, `puppet` classes directly assigned to this are removed upon submitting the information.
Steps to Reproduce:
1. Select and edit a host
2. Switch to the "puppet classes" tab and add a puppet class from the available classes. -> it's in the "included classes" list.
3. Submit the change and verify, that the class is included
4. use another satellite user with less privileges.
5. Select and edit the same host like in step #1
6. Change nothing... but press "Submit"
7. If you verify the "included" classes" list, the entry from step #2 is vanished.
- `puppet` classes removed from host.
- `puppet` classes should not be removed in such situation.