Cephfs Native driver fails to install tempest dependencies

[Carlos Eduardo]

Description
===========
Manila jobs started failing after the base ubuntu image for devstack was migrated to ubuntu 22 by default. It is a community wide goal [1] and all projects should adhere to the newest versions.

The Cephfs Native job started failing to install tempest dependencies. Somehow it seems to be trying to use python2.

Steps to reproduce
==================

Try to setup Manila in a devstack using the Cephfs Native driver.

Expected result
===============
Devstack should set up properly

Actual result
=============
Devstack fails in the step where we try to install tempest dependencies.

Environment
===========
1. Devstack, on master branch (Antelope)

2. Cephfs Native backend

Logs & Configs
==============

Failures [2]

[1] https://governance.openstack.org/tc/goals/selected/migrate-ci-jobs-to-ubuntu-jammy.html
[2] https://paste.opendev.org/show/bCZgAf9uCzOq955P180q/