connectd: at disconnected, tell lightningd how long we were connected.

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

tests/fuzz/connectd_handshake.h

@@ -147,6 +147,7 @@ static struct io_plan *
 success(struct io_conn *conn UNUSED, const struct pubkey *them UNUSED,
 	const struct wireaddr_internal *addr UNUSED, struct crypto_state *cs,
 	struct oneshot *timeout UNUSED, enum is_websocket is_websocket UNUSED,
+	struct timemono starttime UNUSED,
 	void *unused UNUSED)
 {
 	assert(false && "handshake unexpectedly succeeded");