[JM-1276] Added ability for a user provider to require a name and/or email address.  (only used by ClearspaceUserProvider at this time)

git-svn-id: http://svn.igniterealtime.org/svn/repos/openfire/branches/openfire_3_5_0@9980 b35dd754-fafc-0310-a699-88a17e54d16e