Clean up peer logging.

The peer-provided address got appended to the end of each line:

 +0.836160958 DEBUG: seed server supplied 168 bytes of peers2600:3c00::f03c:91ff:fedf:87f4:8323
 +0.836183002 DEBUG: peer_cache adding repeat for 2600:3c00::f03c:91ff:fedf:87f4:8323::ffff:66.228.55.133:8323
 +0.836197505 DEBUG: peer_cache adding repeat for ::ffff:66.228.55.133:8323::ffff:128.199.137.156:8323
 +0.836209405 DEBUG: peer_cache adding repeat for ::ffff:128.199.137.156:83232400:6180:0:d0::bb:3001:8323
 +0.836221552 DEBUG: peer_cache adding repeat for 2400:6180:0:d0::bb:3001:8323

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fix up insufficient peers case.

Reported-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cleaner logging, and less spam at --log-level=info.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Make "info" the default log level.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>