Drop centos8s jobs from experimental pipeline

This is a follow-up to [0], removing jobs also from experimental to
avoid unnecessary runs. Since zuul complains about an empty project
stanza, remove the whole block, it can always be restored from git
history if needed.

[0] I32bef531896777bfb463bb401ebba1d488a16bf9

Change-Id: If68d548957adb8c6584dcab4582ef8396cccf0b2

.zuul.d/centos.yaml

@@ -1,55 +1,4 @@
 ---
-- project:
-    #   check:
-    #     jobs:
-    #       - kolla-build-centos8s
-    #       - kolla-ansible-centos8s-source
-    #       - kolla-ansible-centos8s-source-upgrade
-    #   check-arm64:
-    #     jobs:
-    #       - kolla-build-centos8s-aarch64
-    #   gate:
-    #     jobs:
-    #       - kolla-build-centos8s
-    #       - kolla-ansible-centos8s-source
-    #       - kolla-ansible-centos8s-source-upgrade
-    #   periodic:
-    #     jobs:
-    #       - kolla-publish-centos8s-quay
-    #   periodic-weekly:
-    #     jobs:
-    #       - kolla-publish-centos8s-dockerhub
-    experimental:
-      jobs:
-        - kolla-build-no-infra-wheels-centos8s
-        - kolla-ansible-centos8s-source-bifrost:
-            files: ^docker\/(base|bifrost|openstack-base)\/.*
-        # Test rabbitmq & mariadb changes in multinode ceph jobs.
-        - kolla-ansible-centos8s-source-cephadm:
-            files: ^docker\/(base|cinder|glance|mariadb|openstack-base|rabbitmq)\/.*
-        - kolla-ansible-centos8s-source-upgrade-cephadm:
-            files: ^docker\/(base|cinder|glance|mariadb|openstack-base|rabbitmq)\/.*
-        - kolla-ansible-centos8s-source-zun:
-            files: ^docker\/(base|cinder|etcd|iscsid|kuryr|openstack-base|zun)\/.*
-        - kolla-ansible-centos8s-source-scenario-nfv:
-            files: ^docker\/(base|barbican|heat|mistral|openstack-base|redis|tacker)\/.*
-        - kolla-ansible-centos8s-source-ironic:
-            files: ^docker\/(base|dnsmasq|ironic|ironic-inspector|iscsid|openstack-base)\/.*
-        - kolla-ansible-centos8s-source-swift:
-            files: ^docker/(base|openstack-base|glance|swift)/
-        - kolla-ansible-centos8s-source-mariadb:
-            files: ^docker/(base|mariadb)/
-        - kolla-ansible-centos8s-source-masakari:
-            files: ^docker/(base|masakari)/
-        - kolla-ansible-centos8s-source-octavia:
-            files: ^docker/(base|neutron|octavia|openstack-base|openvswitch|ovn)/
-        - kolla-ansible-centos8s-source-ovn:
-            files: ^docker/(base|neutron|openstack-base|openvswitch|ovn)/
-        - kolla-ansible-centos8s-source-prometheus-efk:
-            files: ^docker/(base|elasticsearch|fluentd|grafana|kibana|prometheus)/
-        - kolla-ansible-centos8s-source-kvm:
-            files: ^docker/nova/
-
 - job:
     name: kolla-build-centos8s
     parent: kolla-base