Fix buildbreak on CentOS with g++ 4.4.7

Change-Id: I3544ebf637d171193e305d1fc61bbf72ab87f17c
Reviewed-on: http://review.couchbase.org/41443
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>