Include the IPv6 address in the descriptor that is going to be tested for self reachability
For IPv4 we log the address for which we test self reachability. Very useful for debugging.
Since we have IPv6 autodiscovery now, and we try hard to better support IPv6 (yey) we should include in this log line also the IPv6 address that is going to be tested for self reachability (if one exists of course and the relay/bridge is not IPv4 only).
Relays / bridges are not marked as running by directory authorities if they advertise an IPv6 address but are not reachable on it, so it makes full sense for the operators to know which address is being tested.