erp5_catalog: Add allowed_types for ERP5Catalog tool

product/ERP5Catalog/ERP5Catalog.py

@@ -52,6 +52,7 @@ class ERP5Catalog(Folder, Catalog):
 
   meta_type = "ERP5 Catalog"
   portal_type = 'Catalog'
+  allowed_types = ()
   #TODO(low priority): Add an icon to display at ERP5 Zope interface
   icon = None
   security = ClassSecurityInfo()