Windows: Replace ParentObjectInformation pointer

Although rare there have been crashes which were the result of
the ObjectInformationCB being freed while another ObjectInformationCB
is pointing to it via the ParentObjectInformation pointer.

This patchset removes the pointer and replaces it with the ParentFileId
which is used to lookup the Parent ObjectInformationCB via the VolumeCB
BTree of all volume objects. The reference counting rules remain the
same.

Change-Id: Iaf66587be2619c8c2f06cd586ef8d423b76d1e79
Reviewed-on: http://gerrit.openafs.org/8993
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>