Windows: Track file server lock count

Windows: Track file server lock count

The fsLockCount field is the lock count reported by the
file server as part of the status info.  Lock acquisition
and releasing does not obtain new status info but we can
estimate what the lock count is by tracking it ourselves
for each of our successful RXAFS_SetLock and RXAFS_ReleaseLock
RPCs and failed RXAFS_ExtendLock RPCs.

Change-Id: Ib5dc5853d82a1292e848bf67d4d9932485177d91
Reviewed-on: http://gerrit.openafs.org/5298
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>