Provide guidance to users that remove JIRA OnDemand from their Google domain

It is possible for customers using Google Apps integration to remove JIRA OnDemand from their Google domain using the Google Apps control panel. This breaks integration with OnDemand, but doesn't really provide them with any feedback. It does not trigger a request to convert to a non-Gapps-enabled OnDemand instance, or cancel their subscription to OnDemand. This can catch them by surprise.

It would be good if we could detect when they have removed the Gapps integration and provide guidance about what their options are.