Windows: Report actual volume creation time

The cm_scache.volumeCreationDate is populated by any non-bulkstat
callback issuing operation.  If it is not set at the time the
redirector requests volume information, force an RXAFS_FetchStatus
and then use the resulting timestamp in the response.

Change-Id: I8ab471767dd6525efc71deff073d54ae38f1f462
Reviewed-on: http://gerrit.openafs.org/9554
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>