swift3 does not handle 202 status code

[Christof Schmitt]

The object server can return a 409 status code that gets turned into a 202 status code in swift, see swift/swift/proxy/controllers/obj.py:

            self.app.logger.debug(
                _('Object PUT returning 202 for 409: '
                  '%(req_timestamp)s <= %(timestamps)r'),
                {'req_timestamp': req.timestamp.internal,
                 'timestamps': ', '.join(status_times)})
            raise HTTPAccepted(request=req)

The current swift3 code turns that into a "500 Internal Server Error" "unexpected status code".