Remove compile warnings

Change-Id: Ib2f208340e20e3fef79707ac7a95e08efecf396c
Reviewed-on: http://review.couchbase.org/24772
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>