erp5_graph_editor: fix ? a seems to be wrong code.

bt5/erp5_graph_editor/SkinTemplateItem/portal_skins/erp5_graph_editor/Workflow_getGraph.xml

@@ -93,7 +93,7 @@ def getWorkflowGraph(workflow):\n
           transition_id_list.append(transition_id)\n
 \n
     if transition_id_list != []:\n
-      graph[\'edge\']["%s_%s" % (state.getId(), transition_id_list)] = (\n
+      graph[\'edge\'][state.getId()] = (\n
               dict(_class=\'workflow.transition\',\n
                    source=state.getId(),\n
                    destination=state.getId(),\n