CCBC-288: Fail NOT_MY_VBUCKET responses on timeout

Unfortunately we don't have a proper way of verifying this for now. The
mock should be updated to simulate more realistic rebalance scenarios

Change-Id: I6b66b69552abe68545086be0b1a6e8d058f7138a
Reviewed-on: http://review.couchbase.org/29924
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>