Fix for #457

Error is due because there is a value for 'stray_list_input_path'

Author: Luci2015

user_sync/app.py

@@ -311,8 +311,8 @@ def begin_work(config_loader):
     additional_groups = rule_config.get('additional_groups', None)
     if additional_groups and isinstance(additional_groups, list):
         additional_group_filters = [r['source'] for r in additional_groups]
-
-    directory_connector.state.additional_group_filters = additional_group_filters
+    if directory_connector is not None:
+        directory_connector.state.additional_group_filters = additional_group_filters
 
     primary_name = '.primary' if secondary_umapi_configs else ''
     umapi_primary_connector = user_sync.connector.umapi.UmapiConnector(primary_name, primary_umapi_config)