A couple of minor fixes.

I'm guessing that non-200 status codes weren't being converted because they when there's an error on the server the response might not be JSON/XML. However, client errors are [guaranteed by the GeoReport spec to be formatted as such](http://wiki.open311.org/GeoReport_v2#Errors). Therefore it is only actual server errors, 5xx, that might not actually be JSON/XML. 400, 403, 404, etc. should all be safe.