[curl] Experiment halted after the first alphabet in Omniglot

The issue is for the CURL folder.

Here is my command to launch the training job:
```
PYTHONPATH=`pwd`/..:$PYTHONPATH python3 train_main.py --dataset='omniglot'
```

After 2000 training steps, it shows:
```
2022-11-14 00:03:59.610492: W ./tensorflow/core/framework/model.h:213] Encountered a stop event that was not preceded by a start event.
```
It seems that training is halted unexpectedly after the first alphabet (2000 steps). But there is still CPU usage.