v1alpha7 e2e tests are actually testing v1alpha6

[mdbooth]

/kind bug

This can be seen clearly in the v1alpha7 kustomization, which references v1alpha6, and verified to running make e2e-templates and checking the contents of the v1alpha7 test template.

cluster-api-provider-openstack/test/e2e/data/kustomize/v1alpha7/kustomization.yaml

Lines 1 to 4 in 62dda69

	apiVersion: kustomize.config.k8s.io/v1beta1
	kind: Kustomization
	resources:
	- ../../../../../kustomize/v1alpha6/external-cloud-provider

The impact is that our v1alpha7 e2e test is actually testing v1alpha6.

[kashifest]

I think this issue is also good to close as I can see a fix here #2028 @mdbooth