Windows: Correct cm_volume locking

Windows: Correct cm_volume locking

cm_volume_t flags was used for two categories of flags.  The first
protected by the cm_volume_t->rw lock.  The second protected by
the global cm_volumeLock.  Separate the flags field into two
afs_uint16 fields and break the flag space into FLAG and QFLAG.

Add assertions to the volume LRU functions to ensure that they
are always called with cm_volumeLock write-locked.

Correct two locations where cm_AdjustVolumeLRU() was called
read-locked instead of write-locked.

Change-Id: I7991b995a3c981cd5d08d9cbba09badc81518a5a
Reviewed-on: http://gerrit.openafs.org/3760
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>