CI: Add CentOS KVM job

Follow-up on [1] which added Ubuntu.

[1] https://review.opendev.org/735454

Change-Id: If0baef37db392324c285798fa55d5e85892edb9f

zuul.d/jobs.yaml

@@ -36,6 +36,14 @@
       install_type: source
       tls_enabled: true
 
+- job:
+    name: kolla-ansible-centos8-source-kvm
+    parent: kolla-ansible-kvm-base
+    nodeset: kolla-ansible-centos8-nested-virt
+    vars:
+      base_distro: centos
+      install_type: source
+
 - job:
     name: kolla-ansible-ubuntu-source-kvm
     parent: kolla-ansible-kvm-base

zuul.d/nodesets.yaml

@@ -88,3 +88,9 @@
     nodes:
       - name: primary
         label: nested-virt-ubuntu-bionic
+
+- nodeset:
+    name: kolla-ansible-centos8-nested-virt
+    nodes:
+      - name: primary
+        label: nested-virt-centos-8

zuul.d/project.yaml

@@ -14,6 +14,7 @@
         - kolla-ansible-centos8-source
         - kolla-ansible-debian-source
         - kolla-ansible-ubuntu-source
+        - kolla-ansible-centos8-source-kvm
         - kolla-ansible-ubuntu-source-kvm
         - kolla-ansible-ubuntu-source-multinode-ipv6
         - kolla-ansible-centos8-source-bifrost