message: fix http_client invalid read.
diff: @@ -1427,7 +1427,7 @@ static PHP_METHOD(swoole_http_client, __construct)
  static PHP_METHOD(swoole_http_client, __destruct)
  {
  http_client *http = swoole_get_object(getThis());
  - if (http && http->cli->released == 0)
  + if (http && http->cli && http->cli->released == 0)
  {
  zval *zobject = getThis();
  zval *retval = NULL;
  