Allow build with CUDA 9.0
Allow build with CUDA 9.0

Summary:
This correctly adds handling of CUDA 8.0 and 9.0 by cmake.

**Discussion:**
CUDA 9.0 is currently not handled by cmake. When trying to build
with it and gcc6, the following cmake error is shown:

-- CUDA detected: 9.0
...
CMake Error at cmake/Dependencies.cmake:332 (message):
  CUDA 8.0 is not compatible with GCC version >= 6.  Use the following option
  to use another version (for example):
    -DCUDA_HOST_COMPILER=/usr/bin/gcc-5
Closes https://github.com/caffe2/caffe2/pull/1392

Differential Revision: D6317033

Pulled By: pietern

fbshipit-source-id: 08b89f21b994af52533d5afaaa62f26e2e94aee8

Yangqing/caffe2,sf-wind/caffe2,caffe2/caffe2,davinwang/caffe2,Yangqing/caffe2,davinwang/caffe2,sf-wind/caffe2,pietern/caffe2,xzturn/caffe2,xzturn/caffe2,Yangqing/caffe2,sf-wind/caffe2,xzturn/caffe2,Yangqing/caffe2,pietern/caffe2,sf-wind/caffe2,davinwang/caffe2,pietern/caffe2,pietern/caffe2,sf-wind/caffe2,davinwang/caffe2,Yangqing/caffe2,davinwang/caffe2,xzturn/caffe2,pietern/caffe2,xzturn/caffe2