audit message missing for autostop

call onStop when auto stopping (elastic#43984)

fixes elastic#43977

Author: Hendrik Muhs

x-pack/plugin/data-frame/src/main/java/org/elasticsearch/xpack/dataframe/transforms/DataFrameTransformTask.java

@@ -657,6 +657,7 @@ protected void doSaveState(IndexerState indexerState, Map<String, Object> positi
                             r -> {
                                 // for auto stop shutdown the task
                                 if (state.getTaskState().equals(DataFrameTransformTaskState.STOPPED)) {
+                                    onStop();
                                     transformTask.shutdown();
                                 }
                                 next.run();
@@ -715,7 +716,7 @@ protected void onFinish(ActionListener<Void> listener) {
         @Override
         protected void onStop() {
             auditor.info(transformConfig.getId(), "Data frame transform has stopped.");
-            logger.info("Data frame transform [{}] indexer has stopped", transformConfig.getId());
+            logger.info("Data frame transform [{}] has stopped", transformConfig.getId());
         }
 
         @Override