Windows: interlocked ops for osi lock flags

Windows: interlocked ops for osi lock flags

Use interlocked operations to set and clear the flags in the osi
mutex and readwrite lock objects.

Change-Id: I92089650d3474efb76c45293b5209b3e2350d983
Reviewed-on: http://gerrit.openafs.org/7720
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>