1. If a request was redirected or some error was encountered, we
try to reset the uploading byte-device.
2. Disconnecting from the byte-device is not enough, since we have a
queued connection, _q_uploadDataReadyRead() gets called even if
byte-device was deleted and thus sender() can return null -
we have to check this condition.
3. Update auto-test with a case where our server immediately
replies with a redirect status code.
Task-number: QTBUG-67469
Task-number: QTBUG-66913
Change-Id: I9b364cf3dee1717940ddbe50cba37c3398cc9c95
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
9917eb2ec6