REFACTOR: Replaced deprecated property_path => false to mapped => false

Form/Type/AdminType.php

@@ -28,7 +28,7 @@ class AdminType extends AbstractType
         $admin = $this->getAdmin($options);
 
         if ($options['delete'] && $admin->isGranted('DELETE') ) {
-            $builder->add('_delete', 'checkbox', array('required' => false, 'property_path' => false));
+            $builder->add('_delete', 'checkbox', array('required' => false, 'mapped' => false));
         }
 
         if (!$admin->hasSubject()) {