Created by: QiJune

fix #8536 (closed)

Please refer to https://docs.nvidia.com/deeplearning/sdk/pdf/NCCL-Installation-Guide.pdf.

If we install nccl as following:

sudo apt-get install libnccl2 libnccl-dev

2.1.4-1+cuda9.1 version will be installed.

However, our docker environment is cuda 8.0. We must install right version of nccl

sudo apt-get install libnccl2=2.1.2-1+cuda8.0 libnccl-dev=2.1.2-1+cuda8.0

I have test the nccl_test after installing the right version of nccl. It's good.