bad cmake checked into libvbucket, use last good rev.

Change-Id: I264af914f5381ab77d41c3174b6f1779f6def803
Reviewed-on: http://review.couchbase.org/27999
Reviewed-by: Junyi Xie <junyi.couchbase@gmail.com>
Tested-by: Junyi Xie <junyi.couchbase@gmail.com>