Adding extra linear to semantic hashing discretization bottleneck.

[martiansideofthemoon]

This fixes the semantic hashing bug mentioned here https://github.com/tensorflow/tensor2tensor/blob/master/tensor2tensor/models/research/transformer_vae.py#L870
@dustinvtran, @lukaszkaiser is this the correct way to fix this bug?

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[martiansideofthemoon]

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[afrozenator]

Hey @martiansideofthemoon -- thanks so much for the fix, I'll merge this in shortly, but would it be easy to add a unit test too to check if the fix works?

[martiansideofthemoon]

Hi @afrozenator, what kind of a unit test would be useful? Should I compare the shapes of the input / output?

[afrozenator]

Thanks a lot again for doing this @martiansideofthemoon ! Merging this now.

[afrozenator]

@martiansideofthemoon --

Hi @afrozenator, what kind of a unit test would be useful? Should I compare the shapes of the input / output?

Yes, anything to make sure that things run should be fine.