Tox failing in stx/utilities due to libvirt

[Al Bailey]

Nov 6th saw the release of a new version of python-libvirt (5.8.0)
That libvirt does not install in zuul on an Ubuntu machine

  File "/tmp/pip-install-a325xk8l/libvirt-python/setup.py", line 40, in check_minimum_libvirt_version
      spawn([get_pkgcfg(),
  File "/tmp/pip-install-a325xk8l/libvirt-python/setup.py", line 36, in get_pkgcfg
      raise Exception("pkg-config binary is required to compile libvirt-python")
  Exception: pkg-config binary is required to compile libvirt-python

Probably going to fix this by using an upper constraint.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/693409

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/693409
Committed: https://git.openstack.org/cgit/starlingx/utilities/commit/?id=1f024e87ac533ee5fd6131cf7f57750d27fbba34
Submitter: Zuul
Branch: master

commit 1f024e87ac533ee5fd6131cf7f57750d27fbba34
Author: Al Bailey <email address hidden>
Date: Thu Nov 7 13:03:37 2019 -0600

    Fix pylint zuul error due to python-libvirt version

    Nov 6th saw the release of a new version of python-libvirt.
    tox.ini did not have an upper-constraint set for it,
    so we picked up that version, which caused zuul to fail
    in pylint.

    Adding an upper-constraint to fix the issue.

    This allows all reviews in stx/utilities to pass zuul
    and be able to merge.

    Change-Id: Idcdf37fbfb2f8745aadff9aacba828e8166dbc46
    Closes-Bug: 1851707
    Signed-off-by: Al Bailey <email address hidden>

[Ghada Khalil (gkhalil)]

Marking as stx.3.0 / high priority since this would prevent code from merging in stx/utilities