Adding cudatoolkit to ppc64le images

[jakirkham]

Currently the ppc64le images lack cudatoolkit as noted here. Ideally we would like to cache the cudatoolkit packages as is done in the x86_64 images. In order to do this we would need to build out cudatoolkit packages with ppc64le support, which amounts to making a couple PRs ( AnacondaRecipes/cudatoolkit-feedstock#4 ). Once that is done and the packages built, it should be straightforward to add these lines to the Docker image.

[leofang]

Ref: AnacondaRecipes/cudatoolkit-feedstock#6

[jakirkham]

Done in PR ( #178 )