Fix failures in the winbind struct-based test.

Fix failures in the winbind struct-based test.

Don't try to pass the 'privileged' socket directory around for expected value testing - it is just too hard...

A better test (once we unify the winbind protocol with Samba3) would
be a operation to see if you are on the priv pipe, and that will give
acutal end-to-end testing.

Andrew Bartlett
(This used to be commit 2d4103518ab8a7286e65347b8b9b0ccb660e69f6)