MAGETWO-99567: Update Url ActionList

Author: OlgaVasyltsun

lib/internal/Magento/Framework/App/Router/ActionList.php

@@ -1,13 +1,15 @@
 <?php
 /**
- *
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
 namespace Magento\Framework\App\Router;
 
 use Magento\Framework\Module\Dir\Reader as ModuleReader;
 
+/**
+ * Class to retrieve action class.
+ */
 class ActionList
 {
     /**
@@ -74,6 +76,7 @@ public function get($module, $area, $namespace, $action)
         if ($area) {
             $area = '\\' . $area;
         }
+        $namespace = strtolower($namespace);
         if (strpos($namespace, self::NOT_ALLOWED_IN_NAMESPACE_PATH) !== false) {
             return null;
         }