Fixed "return" with discarding invalid chunked body. When ngx_http_discard_request_body() call was added to ngx_http_send_response(), there were no return codes other than NGX_OK and NGX_HTTP_INTERNAL_SERVER_ERROR. Now it can also return NGX_HTTP_BAD_REQUEST, but ngx_http_send_response() still incorrectly transforms it to NGX_HTTP_INTERNAL_SERVER_ERROR. The fix is to propagate ngx_http_discard_request_body() errors.