Windows: fix cm_ServerFindByUUID

opr_uuid_equal() returns non-zero if equal.

Change-Id: I6777d4536d002ec227454aa014278e0fc32eb14d
Reviewed-on: http://gerrit.openafs.org/10090
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>