modify tensorflow checkpoint path

The saved checkpoint stored the model absolute path. If you changed some path, you need to update the stored paths in checkpoint.

Two functions in
https://github.com/tensorflow/tensorflow/blob/r1.6/tensorflow/python/training/saver.py

1. get original state
get_checkpoint_state(checkpoint_dir, latest_filename=None)

2. Update the paths, similar in the got paths

def update_checkpoint_state(save_dir,model_checkpoint_path,
all_model_checkpoint_paths=None,
latest_filename=None)

# all_model_checkpoint_paths is a list