onchaind: use normal feerate, not last feerate from transaction.

This is used by onchaind when creating its own transactions.  Note we
don't send updates yet.

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

lightningd/peer_control.c

@@ -1400,7 +1400,8 @@ static enum watch_result funding_spent(struct peer *peer,
 				  &peer->channel_info->remote_per_commit,
 				  peer->our_config.to_self_delay,
 				  peer->channel_info->their_config.to_self_delay,
-				  peer->channel_info->feerate_per_kw,
+				  get_feerate(peer->ld->topology,
+					      FEERATE_NORMAL),
 				  peer->our_config.dust_limit_satoshis,
 				  &peer->channel_info->theirbase.revocation,
 				  &our_last_txid,