Remove openshift + zuul registry testing

The openshift testing relied on openshift 3.11 as this version of
openshift can be deployed locally without using baremetal management.
Unfortunately, docker images for this version of openshift are no longer
available leading to errors like:

  pod_workers.go:186] Error syncing pod b14b1b90-cb64-11ee-816f-bc764e2013fc ("openshift-service-cert-signer-operator-6d477f986b-qx6cs_openshift-core-operators(b14b1b90-cb64-11ee-816f-bc764e2013fc)"), skipping: failed to "StartContainer" for "operator" with ImagePullBackOff: "Back-off pulling image \"openshift/origin-service-serving-cert-signer:v3.11\""

When deploying this version of openshift. Since openshift 4 is not
generally installable in a similar manner we drop the testing. The
testing of the registry with other versions of kubernetes should give us
reasonable coverage.

Change-Id: I6ac87edee2123a5105f3b8138157faa7ecd94b0d

zuul-tests.d/container-roles-jobs.yaml

@@ -352,7 +352,6 @@
       - roles/run-buildset-registry/.*
       - roles/use-buildset-registry/.*
       - test-playbooks/registry/.*
-      - zuul-tests.d/container-roles-jobs.yaml
     pre-run: test-playbooks/registry/buildset-registry-pre.yaml
     run: test-playbooks/registry/buildset-registry.yaml
     post-run: test-playbooks/registry/test-registry-post.yaml
@@ -384,34 +383,6 @@
     vars:
       container_command: podman
 
-- job:
-    name: zuul-jobs-test-registry-buildset-registry-openshift-docker
-    dependencies: zuul-jobs-test-registry-buildset-registry
-    description: |
-      Test a buildset registry with openshift and docker
-
-      It is not meant to be used directly but rather run on changes
-      to roles in the zuul-jobs repo.
-    files:
-      - roles/pull-from-intermediate-registry/.*
-      - roles/push-to-intermediate-registry/.*
-      - roles/ensure-docker/.*
-      - roles/ensure-openshift/.*
-      - roles/ensure-package-repositories/.*
-      - roles/build-docker-image/.*
-      - roles/run-buildset-registry/.*
-      - roles/use-buildset-registry/.*
-      - test-playbooks/registry/.*
-    run: test-playbooks/registry/buildset-registry-openshift-docker.yaml
-    post-run:
-      - test-playbooks/registry/test-registry-post.yaml
-    vars:
-      container_command: docker
-    nodeset:
-      nodes:
-        - name: controller
-          label: centos-7
-
 - job:
     name: zuul-jobs-test-registry-buildset-registry-k8s-microk8s
     dependencies: zuul-jobs-test-registry-buildset-registry
@@ -627,7 +598,6 @@
         - zuul-jobs-test-registry-podman
         - zuul-jobs-test-registry-buildset-registry
         - zuul-jobs-test-registry-buildset-registry-k8s-crio
-        - zuul-jobs-test-registry-buildset-registry-openshift-docker
         - zuul-jobs-test-registry-buildset-registry-k8s-microk8s
         - zuul-jobs-test-ensure-kubernetes-crio-ubuntu-focal
         - zuul-jobs-test-ensure-kubernetes-crio-ubuntu-jammy