No image found from docker.io in release qulification

[yutongz]

I0129 07:47:35.495] echosrv-deployment-1664016432-0wfgj    0/2       Init:ImagePullBackOff   0          3m
I0129 07:47:35.495] echosrv-deployment-1664016432-x13p5    0/2       Init:ImagePullBackOff   0          3m


I0129 07:45:24.647]  error: unable to upgrade connection: container not found ("echosrv")

Refer: https://k8s-gubernator.appspot.com/build/istio-prow/pull/istio-releases_daily-release/351/daily-e2e-rbac-auth-default/244/

The reasons behind is as following:

1. We build two istioctl in release, one has tag=docker.io baked while other has tag=gcr.io baked.
2. We don't push images to docker.io until final step of release and before, images only stay in gcr.io
3. In -default release-qulification tests, we use the istioctl baked with docker.io (which is the one customers should use after we publishing the release)