CMakeSpecificSettingsPage: delete SettingsWidget

Also added Q_OBJECT macro, for tr call in ctor.

Change-Id: I4766b6299a07e3ba0ebc8577e9f4471021b89f07
Reviewed-by: hjk <hjk@qt.io>

src/plugins/cmakeprojectmanager/cmakespecificsettingspage.cpp

@@ -102,5 +102,11 @@ void CMakeSpecificSettingsPage::apply()
     m_settings->toSettings(Core::ICore::settings());
 }
 
+void CMakeSpecificSettingsPage::finish()
+{
+    delete m_widget;
+    m_widget = nullptr;
+}
+
 } // Internal
 } // CMakeProjectManager