Ticket 47885 - deref plugin should not return references with noc access rights
Bug Description: deref shows derefernced entries for which th client doesn't
have access as dn and empty attribute list
Fix Description: if client has no accesss to the derferernced entry then
omit it from the list in the deref control
In general, if no entries are returned don't send an empty control
https://fedorahosted.org/389/ticket/47885
Reviewed by: noriko, thanks