Windows: Refactor AFSValidateEntry

Windows: Refactor AFSValidateEntry

Refactor AFSValidateEntry to avoid obtaining the
ObjectInformation->Fcb->Resource when it isn't necessary.
This will avoid contention and improve performance.

The only time that the Fcb->Resource is required is when
the object requires verification, the object is a FILE,
and the object was successfully evaluated.

Even with this reorganization there is a small window
of opportunity for a deadlock to occur if a CcPurgeCacheSection()
which is called with the Fcb->Resource held triggers a filter
driver to issue a CreateFile and in between the two operations
an invalidate object is received.

Change-Id: Iddf64f030c6a608ac29a10b7a9a7e130ae6c4249
Reviewed-on: http://gerrit.openafs.org/7143
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>