IFP: Filter with * in infopipe group methods
    
    This patch fixes asterisk in filter of the ListByName Groups' method,
    which ends up calling ifp_groups_list_copy() with a NULL pointer.
    
    Resolves:
    https://pagure.io/SSSD/sssd/issue/3305
    
    Reviewed-by: Fabiano Fidêncio <fidencio@redhat.com>
    Reviewed-by: Pavel Březina <pbrezina@redhat.com>