Fix loading some TALNet models
Fix loading some TALNet models

Summary:
D28728718 cleaned up the "kd_binary_cross_entropy" criterion, but this caused loading old models trained with this criterion to fail.
This diff replaces the "kd_binary_cross_entropy" criterion with the "wav2vec" criterion when loading models, and fixes this error.

It also removes the "log_keys" argument if it's `None`. Some criteria (e.g. wav2vec) require this argument to be a list, and will supply a default value of `[]` when it's absent. The presence of the `None` value prevents the use of this default value and causes an error.

Differential Revision: D28901263

fbshipit-source-id: 9b33aed35e76d2c734d1d4e2cbca1ff193a8c920

pytorch/fairseq,pytorch/fairseq,pytorch/fairseq