Remove old Qt4 to-do comment.

Addressing the comment would likely break existing applications, so
leave things as they are for now.

Task-number: QTBUG-25099
Change-Id: I7dfd0e1ae121dcae57c2babc3373c2e5d16ad44b
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

src/widgets/kernel/qlayoutitem.cpp

@@ -564,10 +564,8 @@ Qt::Orientations QWidgetItem::expandingDirections() const
 
     Qt::Orientations e = wid->sizePolicy().expandingDirections();
     /*
-      ### Qt 4.0:
       If the layout is expanding, we make the widget expanding, even if
-      its own size policy isn't expanding. This behavior should be
-      reconsidered.
+      its own size policy isn't expanding.
     */
     if (wid->layout()) {
         if (wid->sizePolicy().horizontalPolicy() & QSizePolicy::GrowFlag