RunTimeError in "run_summarization": expected device cuda:0 and dtype byte but got device cuda: 0 and dtype Bool
## 🐛 Bug

<!-- Important information -->

Model I am using (Bert, XLNet....):
bertabs-finetuned-cnndm-extractive-abstractive-summarization-pytorch_model

Language I am using the model on (, Chinese....):
English

The problem arise when using:
* [ ] the official example scripts: (give details)  run_summarization.py in examples


The tasks I am working on is:
* [ ] an official GLUE/SQUaD task: summarization


## To Reproduce

Steps to reproduce the behavior:

1.  python run_summarization.py --documents_dir .\data --sumaries_output_dir .\output

<!-- If you have a code sample, error messages, stack traces, please provide it here as well. -->

## Expected behavior

<!-- A clear and concise description of what you expected to happen. -->

## Environment

* OS: Win10
* Python version: 3.6.1
* PyTorch version:1.2.0
* PyTorch Transformers version (or branch): master at 24 Dec
* Using GPU ? Yes
* Distributed of parallel setup ? No
* Any other relevant information:

## Additional context

errors come from modeling_berabs.py, line 328, in forward

Someone suggested to use Pytorch v1.1.0 instead of 1.2.0. But not sure if it is ok. <|||||>it's a version inconsistent issue. 
in ver 1.1.0, torch.gt outputs:
torch.gt(torch.tensor([[1, 2], [3, 4]]), torch.tensor([[1, 1], [4, 4]]))
tensor([[ 0,  1],
        [ 0,  0]], dtype=torch.uint8)
while in ver 1.2.0, it outputs:
>>> torch.ge(torch.tensor([[1, 2], [3, 4]]), torch.tensor([[1, 1], [4, 4]]))
tensor([[True, True], [False, True]])
<|||||>Please see the pull request #2369