Incorrect error response for expired token

[TimHess]

Sending a request to an actuator endpoint with an expired token currently returns HTTP 503 with the following response body:

{
  "security_error": "Cloud controller not reachable"
}

But the following log entry is also written:

 Cloud Foundry returned status: Unauthorized while obtaining permissions from: https://{api.systemdomain}/v2/apps/{appguid}/permissions

[TimHess]

After investigation, this behavior appears to be intentional, though from history it looks to have been related to IIS