Fixed (really this time) the last bug WRT link latencies. This actually wasn't...

Fixed (really this time) the last bug WRT link latencies. This actually wasn't even a latency bug, but it existed beforehand. We only dispatch an update when checking for link timeouts if the link's unicast time just expired and we still have a valid multicast time. Otherwise, we remove the link if both unicast and multicast times are expired. Originally, we were dispatching updates when multicast times were expiring and unicast times were still valid. Such a case results in the link being in the unicast state before and after the multicast expiration; thus, no link update should be dispatched.