Windows: Do not sync callbacks when only need locks

Syncing lock operations with callback fetching is unnecessary because
local lock state is not tracked via callbacks.  More importantly it
risks blocking the cm_LockDaemon thread which needs to be able to
renew locks without obstruction.

Change-Id: Iabe9bb33fef599c4eb0e876e222587ee3e2fdb49
Reviewed-on: http://gerrit.openafs.org/11415
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>