Detach the scrollbars before deleting fExpando.

... when rebuilding the application bar.

This fixes a Deskbar crash on resolution change because the lower
scrollbar is a child of fExpando so it must be removed and deleted
before fExpando is. So the tear down is remote scroll arrows
(if attached) then remote fExpando, then remove the scroll arrow
container view. The application bar is then rebuilt in reverse.

src/apps/deskbar/BarView.cpp

@@ -443,6 +443,9 @@ TBarView::PlaceTray(bool vertSwap, bool leftSwap)
 void
 TBarView::PlaceApplicationBar()
 {
+	if (fScrollArrowView != NULL)
+		fScrollArrowView->DetachScrollers();
+
 	if (fExpando != NULL) {
 		SaveExpandedItems();
 		fExpando->RemoveSelf();