[Bridge\Doctrine] Add "DoctrineType::reset()" method

Author: nicolas-grekas

src/Symfony/Bridge/Doctrine/Form/Type/DoctrineType.php

@@ -280,4 +280,9 @@ public function getParent()
     {
         return 'Symfony\Component\Form\Extension\Core\Type\ChoiceType';
     }
+
+    public function reset()
+    {
+        $this->choiceLoaders = array();
+    }
 }