Windows: non-release only worker threads can release

Windows: non-release only worker threads can release

There are two classes of worker threads created by the service
and donated to the afsredir as part of the reverse ioctl processing
model.  Normal workers can process any kind of ioctl and Release
Only workers that can only process release extent events.

Use a KeWaitForMultipleEvents in the normal worker case to permit
processing any type of event.  The previous implementation excluded
release extent ioctls from the normal workers.

Change-Id: I05e86f62c08e322cf7aa9bdd2fd325919bcbfe8f
Reviewed-on: http://gerrit.openafs.org/6071
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Rod Widdowson <rdw@steadingsoftware.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>