Make centos8 stream job non voting for bug#1957941

Two test_network_basic_ops tests are failing consistently in
centos-8-stream jobs (nova side tempest-integrated-compute-centos-8-stream
and tempest tempest-full-py3-centos-8-stream jobs).

1. tempest.scenario.test_network_basic_ops.TestNetworkBasicOps.test_hotplug_nic
2. tempest.scenario.test_network_basic_ops.TestNetworkBasicOps.test_network_basic_ops

Failure: https://zuul.opendev.org/t/openstack/build/e0db6a9a7ba04e66b0781ba7d259357d/logs

This is blocking nova and tempest gateso making the centos8 stream job
non voting until bug is fixed.

Related-Bug#1957941

Change-Id: Ia8c575b1accf4fa2a25b903bf9bf5a614752e344
2 files changed