Grab images as part of update e2e test

Double quotes around `$KUBECFG` (unless you expect it to be more than a single word), also `${...}` recommended.

Slight style preference for moving the single quote after the = in template. And double quotes around the `${CONTROLLER_NAME}`

```shell
    local pod_id_list=($("${KUBECFG}" -template='{{range.Items}}{{.ID}} {{end}}' -l simpleService="${CONTROLLER_NAME}" list pods))
```