Revert "Travis trying out OpenCL to test GPU."
Revert "Travis trying out OpenCL to test GPU."

This reverts commit e1e4baaeb30a5eecf53e1ddbe54f7d8b982169b1.

bh107/bohrium,bh107/bohrium,madsbk/bohrium,bh107/bohrium,madsbk/bohrium,bh107/bohrium,madsbk/bohrium,madsbk/bohrium