JM-1405: Show an error message when changing the password if the operation is unsupported by the AuthProvider (ex. when Clearspace integration is enabled) instead of making a false claim of a successful password change.

git-svn-id: http://svn.igniterealtime.org/svn/repos/openfire/trunk@10630 b35dd754-fafc-0310-a699-88a17e54d16e