500 error responses to requests with unknown shortnames

[bwmcbride]

Elda responds to requests with unknown shortnames with a 500 internal server error response, e.g.

https://landregistry.data.gov.uk/doc/region/devon.html?_properties=label,sameas

s/sameas/sameAs/ works.

The effect of this can be significant spikes in the rate of 500 errors which trigger ops investigations when some app accessing the api sends a lot of requests containing such errors.

These are bad requests and the correct response is 400 bad request.