f use computed txid from signing session when setting next_funding_txid

Author: dunxen

lightning/src/ln/channel.rs

@@ -8697,7 +8697,7 @@ impl<SP: Deref> FundedChannel<SP> where
 			// Since we have a signing_session, this implies we've sent an initial `commitment_signed`...
 			if !signing_session.has_received_tx_signatures() {
 				// ...but we didn't receive a `tx_signatures` from the counterparty yet.
-				Some(self.funding_outpoint().txid)
+				Some(signing_session.unsigned_tx().compute_txid())
 			} else {
 				// ...and we received a `tx_signatures` from the counterparty.
 				None