isLoggedIn does not respond with valid json

[MrMarvin]

When requesting "/" + Constants.WISEBED_API_VERSION + "/{testbedId}/isLoggedIn" without a valid cookie (speak: not logged in) the API responses with 403 Forbidden status and a body text of You're not logged in into testbed "uzl"!.

Although requested with Accept: application/json the response is plain text which upsets some client implementation that parse the body as JSON.

[MrMarvin]

Response header is: {"CONTENT_TYPE"=>"application/json", "CONNECTION"=>"close", "SERVER"=>"Jetty(8.1.1.v20120215)"}