Comment 4 for bug 1953032

Reviewed: https://review.opendev.org/c/openstack/tripleo-ci/+/820172
Committed: https://opendev.org/openstack/tripleo-ci/commit/caa8675adcc839909ff9290daa7a502fe89db291
Submitter: "Zuul (22348)"
Branch: master

commit caa8675adcc839909ff9290daa7a502fe89db291
Author: Chandan Kumar (raukadah) <email address hidden>
Date: Thu Dec 2 18:33:31 2021 +0530

    Use virtualenv_command as ensure_pip_virtualenv_command

    In tripleo-ci, oooci-build-images[1] and build-containers[2]
    roles, virtualenv_python and virtualenv_command points to
    virtualenv-3.

    On EL9, pip module is throwing error:
    ```
    AttributeError: 'NoneType' object has no attribute 'version_tuple'
    ```

    Switching to ensure_pip_virtualenv_command var
    (comes from ensure_pip role) fixes the issue.

    Python3 is already available on CS7,8 & 9.
    It also removes the hacks related to python-virtualenv and its
    installation.

    Closes-Bug: #1953032
    Closes-Bug: #1745626

    Co-Authored-By: Marios Andreou (marios) <email address hidden>
    Signed-off-by: Chandan Kumar (raukadah) <email address hidden>
    Change-Id: I6de99ca4d6be46960b6061225e4a16c76edc8455