webadmin: model setInfo cleanup

Changed all instances of setInfo() calls on models to
setChangeProhibitionReason(). If there was a hardcoded string passed
to setInfo(), moved it to UIConstants.

Change-Id: I93e67e8b75da1a8409f1229a25bbe514c92bc867
Bug-Url: https://bugzilla.redhat.com/995754
Signed-off-by: Greg Sheremeta <gshereme@redhat.com>