gossip_getnodes_entry was used by gossipd for reporting nodes, and for
reporting peers. But the local_features field is only available for peers,
and most other fields are only available from node_announcement.
Note that the connectd change actually means we get less information
about peers: gossipd used to do the node lookup for peers and include the
node_announcement information if it had it.
Since generate_wire.py can't create arrays-of-arrays, we add a 'struct
peer_features' to encapsulate the two feature arrays for each peer, and
for convenience we add it to lightningd/gossip_msg.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>