message: fix memory leak when senfile failure.
diff: @@ -250,6 +250,7 @@ int swConnection_sendfile(swConnection *conn, char *filename, off_t offset, size
  if (offset < 0 || (length + offset > file_stat.st_size))
  {
  swoole_error_log(SW_LOG_WARNING, SW_ERROR_INVALID_PARAMS, "length or offset is invalid.");
  + error_chunk.store.ptr = task;
  swConnection_sendfile_destructor(&error_chunk);
  return SW_OK;
  }
  