Windows: avoid duplicate volume update queries

Windows: avoid duplicate volume update queries

If multiple volume update queries have stacked up in
cm_UpdateVolumeLocation() and the active query failed,
do not re-issued the blocked queries.  Instead, prevent new
queries for 60 seconds and fail those that blocked during
the active query.

Reviewed-on: http://gerrit.openafs.org/5296
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
(cherry picked from commit 21acdd92c8510a9f99243588388a2a1078547533)

Change-Id: I7f0bc97ca7c194624ac854558bbed6b93a13ce63
Reviewed-on: http://gerrit.openafs.org/6795
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>