HttpUtils - errorGenerator() - always flush
HttpUtils - errorGenerator() - always flush

The automatic flush() on send() happens only in the non-exceptional case, here
we are dealing with exceptions where we need to do it ourself.


Former-commit-id: 0e94c2800907867da44444a59ed4e2bd5c24694f
jolie/jolie,jolie/jolie,jolie/jolie