Remove Qt5 TODO to change QListView semantics.

The comment was written before Qt5 was planned, so it might have
seemed like a good idea to change the semantic with Qt 5.0.

However, as Qt5 is intended to be close to Qt4 in behaviour, this
isn't really a 5.0 change. It can be done any time, but only
optionally and while retaining backwards compatibility.

Change-Id: I8c5c497d13a7ec6574e1cdb6bd411e8b28db876b
Reviewed-by: Thorbjørn Lund Martsum <tmartsum@gmail.com>
Reviewed-by: Girish Ramakrishnan <girish.1.ramakrishnan@nokia.com>
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>

src/widgets/itemviews/qlistview.cpp

@@ -370,8 +370,6 @@ QListView::LayoutMode QListView::layoutMode() const
 
     \sa viewMode
 */
-// ### Qt5: Use same semantic as layouts (spacing is the size of space
-// *between* items)
 void QListView::setSpacing(int space)
 {
     Q_D(QListView);