MINOR: session: set the CO_FL_CONNECTED flag on the connection once ready

If we know there's no handshake, we must set the flag on the connection,
it's not the job of the stream initializer to do it.

src/session.c

@@ -193,6 +193,8 @@ int session_accept_fd(struct listener *l, int cfd, struct sockaddr_storage *addr
 		return 1;
 	}
 
+	/* OK let's complete stream initialization since there is no handshake */
+	cli_conn->flags |= CO_FL_CONNECTED;
 	ret = stream_accept_session(sess, t);
 	if (ret > 0)
 		return ret;