quicly_get_first_timeout should not return "now" if 0rtt is rejecte…

…d, otherwise we'd hot loop

lib/quicly.c

@@ -1428,7 +1428,7 @@ static int scheduler_can_send(quicly_conn_t *conn)
     }
 
     /* scheduler would never have data to send, until application keys become available */
-    if (conn->application == NULL)
+    if (conn->application == NULL || conn->application->cipher.egress.key.aead == NULL)
         return 0;
 
     int conn_is_saturated = !(conn->egress.max_data.sent < conn->egress.max_data.permitted);