Editors: Provide a base implementation for {save,restore}State

Change-Id: Iedfc0d59ecfe257ad5823cff39977bce82ada3a5
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/diffeditor/diffeditoreditable.h

@@ -71,8 +71,6 @@ public:
 
     QWidget *toolBar();
 
-    QByteArray saveState() const;
-    bool restoreState(const QByteArray &state);
 public slots:
     void activateEntry(int index);