json_listpeers returns an array of peers, and an array of nodes: the latter
is a subset of the former, and is used for printing alias/color information.
This changes it so there is a 1:1 correspondance between the peer information
and nodes, meaning no more O(n^2) search.
If there is no node_announce for a peer, we use a negative timestamp
(already used to indicate that the rest of the gossip_getnodes_entry
is not valid).
Other fixes:
1. Use get_node instead of iterating through the node map.
2. A node without addresses is perfectly valid: we have to use the timestamp
to see if the alias/color are set. Previously we wouldn't print that
if it didn't also advertize an address.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
7b735fbeee