connectd: fix fd leak for --offline.

```
**BROKEN** connectd: dev_report_fds: 5 open but unowned?
```

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

connectd/connectd.c

@@ -1543,6 +1543,9 @@ static void connect_activate(struct daemon *daemon, const u8 *msg)
 								 ->is_websocket),
 						       daemon));
 		}
+	} else {
+		for (size_t i = 0; i < tal_count(daemon->listen_fds); i++)
+			close(daemon->listen_fds[i]->fd);
 	}
 
 	/* Free, with NULL assignment just as an extra sanity check. */

tests/test_connection.py

@@ -4409,3 +4409,9 @@ def test_reconnect_no_additional_transient_failure(node_factory, bitcoind):
 
     # We should not see a "Peer transient failure" after restart of l1
     assert not l1.daemon.is_in_log(f"{l2id}-chan#1: Peer transient failure in CHANNELD_NORMAL: Disconnected", start=offset1)
+
+
+def test_offline_fd_check(node_factory):
+    # if get_node starts it, it'll expect an address, so do it manually.
+    l1 = node_factory.get_node(options={"offline": None}, start=False)
+    l1.daemon.start()