Windows: deadlock bet. DirEntry lock + DirectoryNodeHdr.TreeLock

Windows: deadlock bet. DirEntry lock + DirectoryNodeHdr.TreeLock

The DirectoryNodeHdr.TreeLock must be obtained before the
DirEntry->NonPaged->Lock.  In AFSLocateNameEntry(), the
DirEntry lock is obtained before the TreeLock when processing
a symlink object.  For that case obtain the TreeLOCK first.
Drop it if it is not required.

Change-Id: I5b73f98b4bc7fcd5c02b8f255fa2423b52eb4a4d
Reviewed-on: http://gerrit.openafs.org/6558
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>