fix format_err_str function in mytorch.py

[tianyilt]

Hey, Thanks for your help and I succeed in run it. But there may exist some little bug. I try to fix this error type: list has no attribute ravel. The error raises if we run the following: python exp.py --net rnn_vgg16unet3_gruunet4.64.3 --cmd eval --iter last --eval-dsets tat-subseq --eval-scale 0.5 Only np array has attribute ravel. But isinstance(v, (np.ndarray, list)) make list operate list.ravel which will cause error.

Sorry for me can't provide the snapshot because I get off work and forget to save.