Fixes: After adding a new qt version via import, writeSettings()

Task:     Reported on irc

src/plugins/qt4projectmanager/qtversionmanager.cpp

@@ -112,6 +112,7 @@ void QtVersionManager::addVersion(QtVersion *version)
 {
     m_versions.append(version);
     emit qtVersionsChanged();
+    writeVersionsIntoSettings();
 }
 
 void QtVersionManager::updateDocumentation()