Update HAS_GPU variable to account for the CUDA_VISIBLE_DEVICES environment variable.
This is to handle the case where this env var is set to an empty string CUDA_VISIBLE_DEVICES="". In this case RAPIDS cudf and other libaries that use CUDA will not detect a GPU.
Fixes #220
Update HAS_GPU variable to account for the
CUDA_VISIBLE_DEVICESenvironment variable.This is to handle the case where this env var is set to an empty string
CUDA_VISIBLE_DEVICES="". In this case RAPIDS cudf and other libaries that use CUDA will not detect a GPU.