Windows: AFSProcessCreate drop DirOpenRefCount on exit

Windows: AFSProcessCreate drop DirOpenRefCount on exit

AFSProcessCreate() must not maintain its DirOpenReferenceCount
when bFileCreated is true because the AFSCcb maintains its own
count and the one obtained by AFSProcessCreate() will only be
leaked.

Change-Id: I6591eb1c10d3dffe7449894b29c9999f5db91d64
Reviewed-on: http://gerrit.openafs.org/8961
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>