HTTP/2: switched back to RST_STREAM with NO_ERROR. In 8df664ebe037, we've switched to maximizing stream window instead of sending RST_STREAM. Since then handling of RST_STREAM with NO_ERROR was fixed at least in Chrome, hence we switch back to using RST_STREAM. This allows more effective rejecting of large bodies, and also minimizes non-payload traffic to be accounted in the next patch.