fix deprecations: getName → getBlockPrefix

Form/PermissionsGroupType.php

@@ -18,7 +18,7 @@ class PermissionsGroupType extends AbstractType
             ->add('name')
         ;
     }
-    
+
     /**
      * @param OptionsResolverInterface $resolver
      */
@@ -32,7 +32,7 @@ class PermissionsGroupType extends AbstractType
     /**
      * @return string
      */
-    public function getName()
+    public function getBlockPrefix()
     {
         return 'chill_mainbundle_permissionsgroup';
     }