#21160: Adjusting ported pull request to 2.2 version

Author: sivaschenko

app/code/Magento/Backend/Controller/Adminhtml/System/Design/Save.php

@@ -6,12 +6,10 @@
  */
 namespace Magento\Backend\Controller\Adminhtml\System\Design;
 
-use Magento\Framework\App\Action\HttpPostActionInterface;
-
 /**
  * Save design action.
  */
-class Save extends \Magento\Backend\Controller\Adminhtml\System\Design implements HttpPostActionInterface
+class Save extends \Magento\Backend\Controller\Adminhtml\System\Design
 {
     /**
      * Filtering posted data. Converting localized data if needed