ERP5Workflow: don't crash if worklist has not action_box_url set

product/ERP5Workflow/Tool/WorkflowTool.py

@@ -1286,9 +1286,11 @@ def generateActionList(worklist_metadata, worklist_result, portal_url):
     if document_count:
       format_data = metadata['format_data']
       format_data._push({'count': document_count})
+
       append({'name': metadata['worklist_title'] % format_data,
-              'url': '%s/%s' % (portal_url, metadata['action_box_url'] % \
-                                            format_data),
+              'url': portal_url if not metadata['action_box_url'] else \
+                     '%s/%s' % (portal_url,
+                                metadata['action_box_url'] % format_data),
               'worklist_id': metadata['worklist_id'],
               'workflow_title': metadata['workflow_title'],
               'workflow_id': metadata['workflow_id'],