Comment 7 for bug 1825435

I don't see how https://github.com/openstack/oslo.config/commit/6c951ed373f443727a8ea2d10d346ad769285aa2 could be involved because it's not released yet and even if it was, we're hitting this in both py36 (normal with upper-constraints) and lower-constraints jobs, so different versions of oslo.config. Maybe it's a latent bug in oslo.config and something recently changed in nova is tickling it, or there is some other untracked-in-constraints library release around 4/15 that is causing some issues (maybe something in python3.6 itself in the bionic repo?).