Vnd.error links key on json response

[fjginermontagud]

I noticed that "links" key don't has underscore at beginning (_links), and this not conform to the vnd.error specs.

For example:

[
    {
        "logref": "error",
        "message": "Could not find test",
        "links": [
            {
                "rel": "about",
                "href": "http://..."
            }
        ]
    }
]

This vnd.error is produced by this code:

@ControllerAdvice
class TestControllerAdvice {

    @ResponseBody
    @ExceptionHandler(TestNotFoundException.class)
    @ResponseStatus(HttpStatus.NOT_FOUND)
    VndErrors testNotFoundExceptionHandler(TestNotFoundException ex) {
        return new VndErrors(
                "error",
                ex.getMessage(),
                new Link("http://...", "about")
        );
    }
}

[gregturn]

VndErrors is incredibly HAL specific. It leans on having registered the Jackson2HalModule to properly render things.

We clean up the implementation to better match the spec via 4f3be11, but are planning to deprecate the whole things and embrace RFC-7807