MB-9307: Better log message

Change-Id: Idc07ed0947b54d1224d8ed36e548d8f787aa4a3b
Reviewed-on: http://review.couchbase.org/30867
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>
Tested-by: buildbot <build@couchbase.com>