Incorrect error responses

[awlayton]

When an error occurs with the exchange of a code, the status code and body are wrong. The following section describes how the server should respond.

http://tools.ietf.org/html/rfc6749#section-5.2

Tests

To run the relevant oada-conformance tests:

npm run check -- --grep "error responses"

[abalmos]

The "second part" is fixed by OADA/oada-ref-auth-js@3564614 and affabd3.

I think you made up the "first part".