This means remembering the connection direction. We also use the address to try
to reconnect, which we shouldn't bother with if they connect to us.
For peers from the database, we currently always save the addr: we shouldn't really
do this if they connected to us, since it's not useful for reconnecting (we don't
show the addr in JSON reply to listpeers unless we're connected, so it's only an
internal issue). This is left for future work.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>