Windows: minor cm_ioctl corrections

Windows: minor cm_ioctl corrections

remove unused variable

fix a comment to reference correct function name

remove debugging windows event log entry that doesn't
belong in production code

Reviewed-on: http://gerrit.openafs.org/5426
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
(cherry picked from commit d355b4d6fce477e275ac34eb04b3d0f5504dd6fb)

Change-Id: I0fe583c65e6352b9f33786df5a836c4df52301cf
Reviewed-on: http://gerrit.openafs.org/5428
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>