QmlJSEditor: Use preincrement

Change-Id: Ic1db8e0626a7c81bac6dc5bb89a33a55fab2fd6b
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>

src/plugins/qmljseditor/qmloutlinemodel.cpp

@@ -92,7 +92,7 @@ void QmlOutlineItem::setItemData(const QMap<int, QVariant> &roles)
     QMap<int,QVariant>::const_iterator iter(roles.constBegin());
     while (iter != roles.constEnd()) {
         setData(iter.value(), iter.key());
-        iter++;
+        ++iter;
     }
 }