Do not force Qt::PopupFocusReason but let QGuiApp
processActivatedEvent() check the window flags and
do the right thing.

Task-number: QTBUG-41935
Change-Id: Ic97c1d3a7f42a67e43d34b0c035c10d1e26412d7
Reviewed-by: Liang Qi <liang.qi@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>