Code review comment for lp:~jameinel/juju-core/api-set-creds-1199915

LGTM, but please do a little bit of investigation to see if there's a
reaosnably convenient way to reuse the state.APIAddresses code. If not I
can live with it assuming we manage to get rid of this workaround sooner
rather than later -- and I can't see why we *would* keep it around for a
long time, so I'm happy accepting your judgment here.

https://codereview.appspot.com/11137044/