message: Fix for when TF can't initialize the GPU and VisibleDeviceCount returns
  1. Fall back to CPU.
  This happens with '--copt=-fsanitize=address
  linkopt=-fsanitize=address --copt=-fno-omit-frame-pointer'. I haven't
  investigated why, but cuInit returns CUDA_ERROR_OUT_OF_MEMORY.
diff: @@ -183,7 +183,7 @@ TfDualNet::TfDualNet(std::string graph_path)
  worker_threads_.emplace_back(functor, graph_def);
  worker_threads_.emplace_back(functor, graph_def);
  }
  - if (device_count) {
  + if (device_count > 0) {
  return;
  }
  }
  