MAGETWO-56065: [Flat] Filter Exception. Custom attributes mapper move from lib

Author: valdislav

dev/tests/static/testsuite/Magento/Test/Legacy/_files/obsolete_classes.php

@@ -785,6 +785,7 @@
     ['Mage_Core_Model_Config_Fieldset', 'Magento\Core\Model\Fieldset\Config'],
     ['Mage_Core_Model_Config_Options', 'Magento\Framework\Filesystem'],
     ['Magento\Framework\App\Dir', 'Magento\Framework\Filesystem'],
+    ['Magento\Framework\EntityManager\CustomAttributesMapper'],
     ['Magento\Framework\Filesystem\Adapter\Local', 'Magento\Framework\Filesystem\Driver\File'],
     ['Magento\Framework\Filesystem\Adapter\Zlib', 'Magento\Framework\Filesystem\Driver\Zlib'],
     ['Magento\Framework\Filesystem\AdapterInterface'],