Stale bearer token results in 400

[dehora]

When making a request to an upstream authorization server, the API returns 400 instead of indicating an authorization issue.

The response structure is also incorrect - the API definition defines Problem structures for all errors.

One way to reproduce this is to call the server with a stale bearer token.

Example response:

* upload completely sent off: 73 out of 73 bytes
< HTTP/1.1 400 Bad Request
< Server: Apache-Coyote/1.1
< X-Flow-Id: 4d0f0FTwhdXQtqYVYcneMgY5
< X-Content-Type-Options: nosniff
< X-XSS-Protection: 1; mode=block
< Cache-Control: no-cache, no-store, max-age=0, must-revalidate
< Pragma: no-cache
< Expires: 0
< X-Frame-Options: DENY
< Cache-Control: no-store
< Pragma: no-cache
< WWW-Authenticate: Bearer realm="oauth2-resource"
< Content-Type: application/json;charset=UTF-8
< Transfer-Encoding: chunked
< Date: Mon, 08 May 2017 08:43:35 GMT
< Connection: close
< 
{"error":"invalid_request","error_description":"Retrieving information to 'accessToken' failed."}

[lmontrieux]

Jira ticket ARUHA-602