use global python for installing horovod

Author: edknv

tox.ini

@@ -44,8 +44,8 @@ commands =
     python -m pip install --upgrade git+https://github.com/NVIDIA-Merlin/dataloader.git@{posargs:main}
     python -m pip install --upgrade git+https://github.com/NVIDIA-Merlin/nvtabular.git@{posargs:main}
     # Reinstall Horovod using `pip install --no-cache-dir` to build with the new version.
-    {envdir}/env/bin/python -m pip install horovod --no-cache-dir
-    {envdir}/env/bin/horovodrun --check-build
+    python -m pip install horovod --no-cache-dir
+    horovodrun --check-build
     # Install distributed-embeddings.
     git clone https://github.com/NVIDIA-Merlin/distributed-embeddings.git
     cd distributed-embeddings