[katello-devel] Added locking to Katello canned roles

[Partha Aji]

Roles like Adminstrator/Read Everything (which come from the seed 
script) will now automatically be "locked" implying an admin,
1) Cannot add/change/remove permissions related to those roles
2) Cannot rename/change the description of roles

This was done to make maintaining Roles like "Read Everything" 
consistent when migrating on future releases. For example if new 
resource types/read permissions get added, we would want to be able to 
update at least the canned roles to include the new read verbs as a part 
of the permission.

Partha