peer: remove useless map call.

Signed-off-by: Fedor Indutny <fedor@indutny.com>
peer/pool: emit `addr` event on pool. refactor `addr` handler.

Signed-off-by: Fedor Indutny <fedor@indutny.com>
update: use `addr` event to add new peers.

Signed-off-by: Fedor Indutny <fedor@indutny.com>