ERP5Security: make ERP5GroupManager more resistant in extreme cases

When accessing an ERP5 Site, we might have automatic migration of
tools. When this happens, we might not have yet access to scripts
like ERP5Type_asSecurityGroupId.

There was already try/except, so just move slightly more code
inside.

product/ERP5Security/ERP5GroupManager.py

@@ -131,7 +131,6 @@ class ERP5GroupManager(BasePlugin):
         # Fetch category values from defined scripts
         for (method_name, base_category_list) in security_definition_list:
           base_category_list = tuple(base_category_list)
-          method = getattr(self, method_name)
           security_category_list = security_category_dict.setdefault(
                                             base_category_list, [])
           try:
@@ -139,6 +138,7 @@ class ERP5GroupManager(BasePlugin):
             # from here or from _updateLocalRolesOnSecurityGroups.
             # Currently, passing portal_type='' (instead of 'Person')
             # is the only way to make the difference.
+            method = getattr(self, method_name)
             security_category_list.extend(
               method(base_category_list, user_id, person_object, '')
             )
@@ -155,7 +155,7 @@ class ERP5GroupManager(BasePlugin):
         group_id_list_generator = getattr(self, generator_name, None)
         if group_id_list_generator is None:
           generator_name = ERP5TYPE_SECURITY_GROUP_ID_GENERATION_SCRIPT
-          group_id_list_generator = getattr(self, generator_name)
+          group_id_list_generator = getattr(self, generator_name, None)
         for base_category_list, category_value_list in \
             security_category_dict.iteritems():
           for category_dict in category_value_list: