Windows: DirectIO AFS_INVALIDATE_DATA_VERSION

Implement cache flush and purge operations in response to
AFS_INVALIDATE_DATA_VERSION requests when DirectIO processing is in use.

Change-Id: If37ee4b3486a7a112f34bb07cc433f4832fdab8d
Reviewed-on: http://gerrit.openafs.org/9744
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Peter Scott <pscott@kerneldrivers.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Reviewed-on: http://gerrit.openafs.org/9766