Comment 6 for bug 1606617

In 1.25.13 we had this (in config) which worked:

 // CloudImageBaseURL allows a user to override the default url that the
 // 'ubuntu-cloudimg-query' executable uses to find container images. This
 // is primarily for enabling Juju to work cleanly in a closed network.
 CloudImageBaseURL = "cloudimg-base-url"