TripleO jobs: Drop remaining CentOS 8 jobs
TripleO jobs: Drop remaining CentOS 8 jobs

... because now we removed all reference to CentOS 8 jobs.

Depends-on: https://review.opendev.org/c/openstack/puppet-nova/+/828526
Depends-on: https://review.opendev.org/c/openstack/puppet-cinder/+/828527
Depends-on: https://review.opendev.org/c/openstack/puppet-glance/+/828528
Depends-on: https://review.opendev.org/c/openstack/puppet-neutron/+/828529
Depends-on: https://review.opendev.org/c/openstack/puppet-horizon/+/828531
Depends-on: https://review.opendev.org/c/openstack/puppet-keystone/+/828532
Depends-on: https://review.opendev.org/c/openstack/puppet-placement/+/828533
Depends-on: https://review.opendev.org/c/openstack/puppet-openstacklib/+/828534
Depends-on: https://review.opendev.org/c/openstack/puppet-oslo/+/828535
Depends-on: https://review.opendev.org/c/openstack/puppet-swift/+/828536
Depends-on: https://review.opendev.org/c/openstack/puppet-octavia/+/828537
Change-Id: I3016956cdf69202ac1af9476f150f2f76c211bbf

openstack/puppet-openstack-integration,openstack/puppet-openstack-integration,openstack/puppet-openstack-integration