Window: breakout CM error codes into separate header

Window: breakout CM error codes into separate header

Reviewed-on: http://gerrit.openafs.org/5052
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
(cherry picked from a1af69182b12bedd8a413d38cef9a4691286da46)

Change-Id: I82adf60bef97575d47b65561fdc2b097f8ac610a
Reviewed-on: http://gerrit.openafs.org/5131
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>