fix BGR <> RGB swap

we are drawing on a BGR image declared as RGB, so we should not swap
components here either.

modules/highgui/src/window_QT.cpp

@@ -843,7 +843,7 @@ void GuiReceiver::putText(void* arr, QString text, QPoint org, void* arg2)
         //cvScalar(blue_component, green_component, red_component[, alpha_component])
         //Qt map non-transparent to 0xFF and transparent to 0
         //OpenCV scalar is the reverse, so 255-font->color.val[3]
-        qp.setPen(QColor(font->color.val[2], font->color.val[1], font->color.val[0], 255 - font->color.val[3]));
+        qp.setPen(QColor(font->color.val[0], font->color.val[1], font->color.val[2], 255 - font->color.val[3]));
         qp.setFont(f);
     }
     qp.drawText(org, text);