Remove compile warnings

Change-Id: If42fe9ebd56b1c26b3612b11dbc2dcc01ae5141d
Reviewed-on: http://review.couchbase.org/34379
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>