Change default URL of http example to Qt Project page.

The default URL changed to http[s]://qt-project.org site.
This example referred to http[s]://qt.nokia.com site earlier.

Change-Id: I356e8f85f5cb07dc619b0e5eb1da857f8a9b6986
(cherry-picked from qtbase/adc5626f4fdeed30634a950bdaa2404d5e98a4de)
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>