Comment 2 for bug 1876028

Reviewed: https://review.opendev.org/724378
Committed: https://git.openstack.org/cgit/openstack/networking-bgpvpn/commit/?id=0649023d959ba87c57ead2d9d5985d02986ea182
Submitter: Zuul
Branch: stable/ussuri

commit 0649023d959ba87c57ead2d9d5985d02986ea182
Author: Elod Illes <email address hidden>
Date: Wed Apr 29 14:07:52 2020 +0200

    Fix dsvm-functional and cleanup tox.ini

    Remove unnecessary things from tox.ini:
    - install_command: it's better to use the built-in install command
    - VIRTUAL_ENV: this is set anyways
    - sitepackages: it's enough to use virtualenv's packages

    Besides these seem to be unnecessary 'sitepackages' setting started to
    break functional job with an error message that there are missing
    packages, however those were installed. By removing sitepackages=True
    setting the errors dissapear.

    Closes-Bug: #1876028
    Change-Id: Ifc4904fa89eb7fcaaa8cd623112f419ac57ea286
    (cherry picked from commit 1fbfb94bc08859ad2a5398b32b4fe2e64c98724b)