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.

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>
(cherry picked from commit 962a95c21cc82a8bbb1dc1233c91acd7236fc8e4)

Change-Id: I6c60dd770057f665f66bf3cea2d653bbe2524979
Reviewed-on: http://gerrit.openafs.org/3867
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>