QWindowsVistaStyle: Restore altered brush origin.

The line to restore it was missing, and the leftover variable
caused a warning, which was removed in
abe5a0a432 .

Task-number: QTBUG-27828

Change-Id: I00b8b89b07bec38a1660c3a9c61220b6d0d7eb48
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@digia.com>

src/widgets/styles/qwindowsvistastyle.cpp

@@ -715,8 +715,10 @@ void QWindowsVistaStyle::drawPrimitive(PrimitiveElement element, const QStyleOpt
                 QPixmap pixmap;
 
                 if (vopt->backgroundBrush.style() != Qt::NoBrush) {
+                    const QPointF oldBrushOrigin = painter->brushOrigin();
                     painter->setBrushOrigin(vopt->rect.topLeft());
                     painter->fillRect(vopt->rect, vopt->backgroundBrush);
+                    painter->setBrushOrigin(oldBrushOrigin);
                 }
 
                 if (hover || selected) {