Windows: Skip Extent operations if Direct IO

If the redirector is using Direct IO servicing there are no extents
in use.  Skip the AFSFlushExtents, AFSTearDownExtents, and related
calls unless extent processing is in use.  This will reduce lock
contention and reduce cpu processing.

Change-Id: I2948295bdd6056e6fbdab7d32c46575a8a7aebbc
Reviewed-on: http://gerrit.openafs.org/10215
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>
Windows: Add trace to track setting VERIFY flag

Add trace statements at each location the VERIFY flag is set or
cleared.

Change-Id: I108d3d44947bc92f147afb66f746af3262435104
Reviewed-on: http://gerrit.openafs.org/10216
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>