QmlDesigner: cleanup getting propertyEditorQmlSources path

Change-Id: I4a1a8e9d509c8a5357cf98213f41ad70dbd85e3e
Reviewed-by: Marco Bubke <marco.bubke@digia.com>
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: use better reload shortcut

 - an installed QShortcut just eats the shortcut
   so use something more none common

Change-Id: Ibaa898f9e7c979fd6a149f2a56252267bd93ef2d
Reviewed-by: Marco Bubke <marco.bubke@digia.com>
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>