a20ce8c IPA: Use GC for group lookups in server mode

Authored and Committed by jhrozek 9 years ago
    IPA: Use GC for group lookups in server mode
    
    https://fedorahosted.org/sssd/ticket/2412
    
    Even though AD trusts often work with POSIX attributes which are
    normally not replicated to GC, our group lookups are smart since commit
    008e1ee835602023891ac45408483d87f41e4d5c and look up the group itself using
    the LDAP connection and only use the GC connection to look up the members.
    
    Reviewed-by: Pavel Reichl <preichl@redhat.com>