Fix build problems with visual studio 2013

Change-Id: I7dfdcd4f6b6b503c5c49d3fbe77a6c2506ce80ad
Reviewed-on: http://review.couchbase.org/29897
Tested-by: Trond Norbye <trond.norbye@gmail.com>
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>