Add break to the end of all case clauses to prevent fallthrough

Change-Id: I6f85086931610e822b7f1976497909c74e7d09b4
Reviewed-on: http://review.couchbase.org/39710
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>