fixed two problems with the DsRGetDCNameEx2 call, as used by

fixed two problems with the DsRGetDCNameEx2 call, as used by
Win7-beta.

The first problem is that we removed the dnsDomain attribute a while
back, so we were returning NULL for two fields. We now return the
realm.

The second problem is that Win7-beta sends the domain in the form the
user typed it, so it may be in either the short or long form. We check
for the short form and convert if needed.