Qt Quick Controls 1 always creates "native" windows
for popups, however it does not check if the platform
can support creating "native" windows. As a workaround
disable context menu until Qt Quick Controls 2 are
in place.

Task-number: QTBUG-53467
Change-Id: Iea32e19f256f3d7e81a61e23f7da64dfc7ec660d
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>