Windows: AFSNotifyFileCreate() DirOpenReferenceCount handling

This patchset consolidates the releasing of the DirOpenReferenceCount
within AFSNotifyFileCreate() into the try_exit block.  This clarifies
the logic and avoids duplicate code blocks.

Change-Id: I82e964f579f9e8b6e095291ace0bbe2cdac5af60
Reviewed-on: http://gerrit.openafs.org/8855
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>