not all installations offer metrics API, some don't like to be contacted

[donsizemore]

We have basic exception catching, but if an installation isn't new enough to offer the metrics API or doesn't allow the metrics VM to contact its API endpoint, in the case of a 404 it should log a "remove me from config.json" message, and in the case of a 403 it should additionally... clean up any cached data associated with that hostname?

[pdurbin]

Hmm, maybe we could have some way to detect when an existing installation has been upgraded to be new enough to added to config.json?