Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/symfony/routing/Tests/Fixtures/CustomXmlFileLoader.php

@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures;
+
+use Symfony\Component\Routing\Loader\XmlFileLoader;
+use Symfony\Component\Config\Util\XmlUtils;
+
+/**
+ * XmlFileLoader with schema validation turned off.
+ */
+class CustomXmlFileLoader extends XmlFileLoader
+{
+    protected function loadFile($file)
+    {
+        return XmlUtils::loadFile($file, function () { return true; });
+    }
+}