ExamplesListModel: Remove unused/unimplemented methods

Change-Id: I9cecb1f89d07f7b060a2f2b7d228c14c54da8ddf
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/qtsupport/exampleslistmodel.h

@@ -108,15 +108,9 @@ public:
 
     void updateExamples();
 
-    QStringList exampleSets() const;
     ExampleSetModel *exampleSetModel() { return &m_exampleSetModel; }
 
-signals:
-    void selectedExampleSetChanged(int);
-
 private:
-    void updateSelectedQtVersion();
-
     ExampleSetModel m_exampleSetModel;
 };