Comment 9 for bug 1966858

Sorry for the long delay, I have re-run tests on F34 and F35 for (xena and yoga respectively). My testing approach was to spin up instances (2 core 7 ram) from OVH (with private networks attached to get it started), and perform the exact steps indicated in the devstack manual [1], i.e. with `local.conf` looking like:
```
[[local|localrc]]
ADMIN_PASSWORD=secret
DATABASE_PASSWORD=$ADMIN_PASSWORD
RABBIT_PASSWORD=$ADMIN_PASSWORD
SERVICE_PASSWORD=$ADMIN_PASSWORD
DEST=/opt/stack
LOGFILE=$DEST/logs/stack.sh.log
```
(Also setting `chmod 760 /opt/stack`)

For F35, I also had to fix the `pyscss` version in horizon. Otherwise everything should be reproducible as I've described. I have attached the log directory of this, along with `journalctl` of the service, `dnf list --installed 'python*'`, and a copy of `neutron-ovn-metadata-agent` that the service is executing. I can't find why/where python3.8 is used as described.

One thing to note is that the ansible roles that zuul uses and `stack.sh` are not equivalent. Probably the ansible script forces the python version much stricter than pip or the `functions.sh` scripts do.

[1] https://docs.openstack.org/devstack/latest/index.html