Windows: VolumeCB->ObjectInfoTree.TreeLock Deadlock

Windows: VolumeCB->ObjectInfoTree.TreeLock Deadlock

AFSPrimaryVolumeWorkerThread held the VolumeCB->ObjectInfoTree.TreeLock
exclusively across calls to AFSCleanupFcb() which in turn triggers
a file extent release to the service which can in turn result in
an object invalidation.  Processing the invalidation requires shared
access to VolumeCB->ObjectInfoTree.TreeLock which results in a deadlock.

This patch alters the processing of AFSPrimaryVolumeWorkerThread
so that the VolumeCB->ObjectInfoTree.TreeLock is not held across
the AFSCleanupFcb() calls.

FIXES 130431

Change-Id: I3726df02ab47d2dcc83a32c75957a5dafcfbf20e
Reviewed-on: http://gerrit.openafs.org/6724
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Peter Scott <pscott@kerneldrivers.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>