cleanup: Don't shadow variables

Having variables that share the same name in overlapping scopes is
confusing and error-prone, and is best avoided.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/805

js/misc/util.js

@@ -405,7 +405,7 @@ function ensureActorVisibleInScrollView(scrollView, actor) {
         if (!parent)
             throw new Error("actor not in scroll view");
 
-        let box = parent.get_allocation_box();
+        box = parent.get_allocation_box();
         y1 += box.y1;
         y2 += box.y1;
         parent = parent.get_parent();