Qt, sout: fix compilation on older moc version

(cherry picked from commit 04f7cf0afa06dc45e134db6747f53f5c4a085ad8)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/dialogs/sout.hpp

@@ -33,6 +33,8 @@
 #include "ui/sout.h"
 #include "util/qvlcframe.hpp"
 
+#include <QWizard>
+
 class QPushButton;
 class QToolButton;
 class QCheckBox;