Fix compile warning

control reaches end of non-void function [-Wreturn-type]

Change-Id: Ibe5ec2801f304b6fe4f767073628462c90161f93
Reviewed-on: http://review.couchbase.org/42826
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>