Comment 1 for bug 1766677

I think I figured out what's going on. The functional testenv definitions in tox.ini have sitepackages=True. It looks like tox only installs the requirements that aren't already present on the system in that case, so whether you see this message or not depends on whether you have stestr installed somewhere in your path. I guess we could whitelist stestr for this case? Probably not worth worrying about.