MB-100: fix Non-ASCII character in rebalance helper

Change-Id: I112366cec25ddd0feb7f456baed698f100164d0b
Reviewed-on: http://review.couchbase.org/23812
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>