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.

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>
(cherry picked from commit f37b6dfaf050ec0270979c8310fb471c16b66cd3)

Change-Id: I33771780a4ace4aa5b4613bef4590d5efaf15922
Reviewed-on: http://gerrit.openafs.org/6021
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>