Travis: set CUDA_HOME

tests/install_travis.sh

@@ -49,6 +49,8 @@ sudo apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda
 sudo add-apt-repository "deb http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/ /"
 sudo apt-get update
 sudo apt-get -y install cuda-$CUDA_VERSION
+sudo ldconfig
+export CUDA_HOME=/usr/local/cuda
 export PATH=/usr/local/cuda/bin:$PATH
 fi