Add REMOTE_USER_GROUPS to ClaimAuthFilter

The REMOTE_USER_GROUPS IdP attribute was mistakenly omitted from
the medtadata collected in ClaimAuthFilter, this corrects that.

Bug #2272

Change-Id: Ibe7f9afb7b94341beb24ea5474c419b592261ce6
Signed-off-by: John Dennis <jdennis@redhat.com>