Trying to launch a recent 4.11 cluster on OpenStack platform with
```
launch registry.ci.openshift.org/rhcos-devel/rhcos41186:4.11.0-0.nightly-2022-05-10-045003 openstack
```
results in an error.

The `openstack-conf-resourcenames` fails with `OPENSTACK_EXTERNAL_NETWORK value for CLUSTER_TYPE 'openstack-vexxhost' not known.`

https://gcsweb-ci.apps.ci.l2s4.p1.openshiftapps.com/gcs/origin-ci-test/logs/release-openshift-origin-installer-launch-openstack/1524394128316567552/artifacts/launch/openstack-conf-resourcenames/build-log.txt

The same step works fine when launching a 4.10 cluster with `launch 4.10.0-0.ci openstack`

https://gcsweb-ci.apps.ci.l2s4.p1.openshiftapps.com/gcs/origin-ci-test/logs/release-openshift-origin-installer-launch-openstack/1524396242916872192/artifacts/launch/openstack-conf-resourcenames/build-log.txt