Revert "Add debugging for psutil import issue."

This reverts commit 8693f1c991c9e242a3cda8197bbaeaf581997e02.
Revert "Upgrade virtualenv."

This reverts commit fa615ca127b4b64fa350670aed2e33429e99d67a.
Fixup python selection error - use bare python since we're already in a venv.