Zend_Cache: TwoLevels backend properties visibility is changed to 'protected'. ZF-8430.

git-svn-id: http://framework.zend.com/svn/framework/standard/trunk@19787 44c647ce-9c0f-0410-b52a-842ac1e357ba

library/Zend/Cache/Backend/TwoLevels.php

@@ -95,21 +95,21 @@ class Zend_Cache_Backend_TwoLevels extends Zend_Cache_Backend implements Zend_Ca
      *
      * @var Zend_Cache_Backend
      */
-    private $_slowBackend;
+    protected $_slowBackend;
 
     /**
      * Fast Backend
      *
      * @var Zend_Cache_Backend
      */
-    private $_fastBackend;
+    protected $_fastBackend;
 
     /**
      * Cache for the fast backend filling percentage
      *
      * @var int
      */
-    private $_fastBackendFillingPercentage = null;
+    protected $_fastBackendFillingPercentage = null;
 
     /**
      * Constructor