MINOR: peers: use conn->dst for the peer's target address

MINOR: peers: use conn->dst for the peer's target address

The target address is duplicated from the peer's configured one. For
now we keep the target address as-is but we'll have to dynamically
allocate it and place it into the stream instead. Maybe a sockaddr_dup()
will help by the way.

The "show peers" part is safe as it's already called after checking
the addresses' validity.