fix exporting model doc for object detection
fix exporting model doc for object detection

see example usage in https://github.com/tensorflow/models/blob/master/object_detection/export_inference_graph.py#L51
tombstone/models,jiaphuan/models,sshleifer/object_detection_kitti,tombstone/models,jiaphuan/models,tombstone/models,sshleifer/object_detection_kitti,alexgorban/models,derekjchow/models,sshleifer/object_detection_kitti,sshleifer/object_detection_kitti,tombstone/models,cshallue/models,cshallue/models,cshallue/models,alexgorban/models,sshleifer/object_detection_kitti,cshallue/models,alexgorban/models,derekjchow/models,sshleifer/object_detection_kitti,alexgorban/models,tombstone/models,derekjchow/models,jiaphuan/models,derekjchow/models,jiaphuan/models,cshallue/models,tombstone/models,alexgorban/models,jiaphuan/models,jiaphuan/models,derekjchow/models