Windows: improve handling of volume rename

Windows: improve handling of volume rename

The windows cache manager tracks volumes by volume group.
Up to this point all volume location updates have been performed
by the volume name.  What if the volume name was altered?  In this
case the volume location information for the in use volume ids will
fail until a mount point to the new name is queried.  Before
marking the volume group as non-existent attempt to perform a
lookup using either the volume id for the readwrite or readonly
volume.

Change-Id: I51b383150b0186867e1c51a28b01e8483ee470f2
Reviewed-on: http://gerrit.openafs.org/5330
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>