sysdb: add parent_dom to sysdb_get_direct_parents()
Currently sysdb_get_direct_parents() only return direct parents from the
same domain as the child object. In setups with sub-domains this might
not be sufficient. A new option parent_dom is added which allows to
specify a domain the direct parents should be lookup up in. If it is
NULL the whole cache is searched.
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>