mailslot/dsgetdcname: do what XP does and request nt_version 11.

mailslot/dsgetdcname: do what XP does and request nt_version 11.

This allows dsgetdcname to query for a flat, non-dns domain name and
come back with all information about the DC (site names, guid, forest,
etc.) based on a mailslot reply. The version 11 request is downgraded
to version 1 in case we do a query against NT4.

Guenther
(This used to be commit d8b2ff3c8769e8da9c21dec483e6edb7aa2d00f3)