MB-6144: fixed typo

Change-Id: Iac2e45539899ad4c75d4e037fb558b97e139bbda
Reviewed-on: http://review.couchbase.org/25464
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>