connectd: don't be That Node when someone is gossipping crap.

As seen in my logs, we complain about nodes a *lot* (Hi old CLN!).

```
===>1589311 DEBUG   02e01367e1d7818a7e9a0e8a52badd5c32615e07568dbe0497b6a47f9bef89d6af-connectd: peer_out WIRE_WARNING
     139993 DEBUG   lightningd: fixup_scan: block 786151 with 1203 txs
      55388 DEBUG   plugin-bcli: Log pruned 1001 entries (mem 10508118 -> 10298662)
      33000 DEBUG   gossipd: Unreasonable timestamp in 0102000a38ec41f9137a5a560dac6effbde059c12cb727344821cbdd4ef46964a4791a0f67cd997499a6062fc8b4284bf1b47a91541fd0e65129505f02e4d08542b16fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d61900000000000d9d56000ba40001690fe262010100900000000000000001000003e8000001f30000000000989680
      23515 DEBUG   hsmd: Client: Received message 14 from client
      22269 DEBUG   024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605-hsmd: Got WIRE_HSMD_ECDH_REQ
      14409 DEBUG   gossipd: Enqueueing update for announce 0102002f7e4b4deb19947c67292e70cb22f7fac837fa9ee6269393f3c513d0431d52672e7387625856c19299cfd584e1a3f39e0f98df13c99090df9f4d5cca8446776fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d61900000000000e216b0008050001692e1c390101009000000000000003e800000000000013880000004526945a00
      12534 DEBUG   gossipd: Previously-rejected announce for 514127x248x1
      10761 DEBUG   02e01367e1d7818a7e9a0e8a52badd5c32615e07568dbe0497b6a47f9bef89d6af-channeld-chan#70770: Got it!
      10761 DEBUG   02e01367e1d7818a7e9a0e8a52badd5c32615e07568dbe0497b6a47f9bef89d6af-channeld-chan#70770: ... , awaiting 1120
      10761 DEBUG   02e01367e1d7818a7e9a0e8a52badd5c32615e07568dbe0497b6a47f9bef89d6af-channeld-chan#70770: Sending master 1020
```

Signed-off-by: Rusty Russell <[email protected]>

Author: rustyrussell

gossipd/gossmap_manage.c

@@ -703,9 +703,16 @@ void gossmap_manage_handle_get_txout_reply(struct gossmap_manage *gm, const u8 *
 	 *    - MUST ignore the message.
 	 */
 	if (tal_count(outscript) == 0) {
-		peer_warning(gm, pca->source_peer,
-			     "channel_announcement: no unspent txout %s",
-			     fmt_short_channel_id(tmpctx, scid));
+		/* Don't flood them: this happens with pre-25.12 CLN
+		 * nodes, which lost their marbles about some old
+		 * UTXOs. */
+		static struct timemono prev;
+		if (time_greater(timemono_since(prev), time_from_sec(1))) {
+			peer_warning(gm, pca->source_peer,
+				     "channel_announcement: no unspent txout %s",
+				     fmt_short_channel_id(tmpctx, scid));
+			prev = time_mono();
+		}
 		goto bad;
 	}