Windows: FCB cleanup must be done before ObjectInfo

Windows: FCB cleanup must be done before ObjectInfo

When processing the cleanup and destruction of a File Control Block
the related ObjectInfoCB is required for proper cleanup.  Reorganize
the AFSPrimaryVolumeWorkerThread logic to ensure that this is true.
This involves dropping the VolumeCB->ObjectInfoTree.TreeLock around
the AFSCleanupFcb() call. While the lock is released it is possible
for the ObjectInfoCB->OpenReferenceCount to change.  Therefore, new
checks must be added after the lock is re-acquired to ensure that
an in-use object is not destroyed.

Change-Id: I6b26fb2fe1ef4077c6edd643ec40715c8e2928ac
Reviewed-on: http://gerrit.openafs.org/7327
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>