ProjectExplorer: Remove unused code

Change-Id: Id8fdb51412717e2123acedc0c15969d3220e9b4e
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/projectexplorer/buildsettingspropertiespage.cpp

@@ -167,11 +167,6 @@ void BuildSettingsWidget::clearWidgets()
     m_labels.clear();
 }
 
-QList<NamedWidget *> BuildSettingsWidget::subWidgets() const
-{
-    return m_subWidgets;
-}
-
 void BuildSettingsWidget::updateAddButtonMenu()
 {
     m_addButtonMenu->clear();

src/plugins/projectexplorer/buildsettingspropertiespage.h

@@ -52,7 +52,6 @@ public:
 
     void clearWidgets();
     void addSubWidget(NamedWidget *widget);
-    QList<NamedWidget *> subWidgets() const;
 
 private:
     void updateBuildSettings();