Create visualwakewords dataset using slim scripts instead of custom scripts (#7796)

* Internal changes to tf.contrib symbols

PiperOrigin-RevId: 277940048

* Create visualwakewords dataset using slim scripts instead of custom scripts.

PiperOrigin-RevId: 278917344

* update for python3.0 compatibility

research/slim/datasets/download_and_convert_visualwakewords_lib.py

@@ -201,7 +201,7 @@ def create_tf_record_for_visualwakewords_dataset(annotations_file, image_dir,
     groundtruth_data = json.load(fid)
     images = groundtruth_data['images']
     annotations_index = groundtruth_data['annotations']
-    annotations_index = {int(k): v for k, v in annotations_index.iteritems()}
+    annotations_index = {int(k): v for k, v in annotations_index.items()}
     # convert 'unicode' key to 'int' key after we parse the json file
 
     for idx, image in enumerate(images):