Windows: ensure TreeLock obtain and release same pointer

Windows: ensure TreeLock obtain and release same pointer

The indirection ObjectInformation->ParentObjectInformation does
not appear to be stable.  When acquiring and releasing a parent
TreeLock, use a local variable to store the ParentObjectInformation
pointer and use that to access the TreeLock.  This will ensure that
the resource obtained is the one that is released.

Change-Id: If359de0f7572cfa4e401baa47affa6872b79e932
Reviewed-on: http://gerrit.openafs.org/7651
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>