Windows: add KTC_TOKEN_MUTEX_FAIL error code

Windows: add KTC_TOKEN_MUTEX_FAIL error code

If acquisition of the Global\AFS_KTC_Mutex fails, return a
different error code from a pioctl failure since the pioctl
was never issued.

Change-Id: I001227f87e97a06bf419c68d6579843e4f93f032
Reviewed-on: http://gerrit.openafs.org/6710
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>