On qt version change updat qmakestep config widget

That is the effective qmake command and summary label.

src/plugins/qt4projectmanager/qt4project.cpp

@@ -984,6 +984,7 @@ int Qt4Project::qtVersionId(BuildConfiguration *configuration) const
 void Qt4Project::setQtVersion(BuildConfiguration *configuration, int id)
 {
     configuration->setValue(KEY_QT_VERSION_ID, id);
+    emit qtVersionChanged(configuration);
     updateActiveRunConfiguration();
 }