Start auto save session timer later and let it occur more then once

Fixes regressions introduced by f059018a8e

Change-Id: I9d590580a9d36ac6980a6d170a119ebe33819262
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>

src/plugins/coreplugin/mainwindow.cpp

@@ -229,9 +229,7 @@ MainWindow::MainWindow() :
     setAcceptDrops(true);
 
     m_autoSaveSessionTimer = new QTimer(this);
-    m_autoSaveSessionTimer->setSingleShot(true);
     m_autoSaveSessionTimer->setInterval(10000);
-    m_autoSaveSessionTimer->start();
     connect(m_autoSaveSessionTimer, SIGNAL(timeout()),
             m_coreImpl, SIGNAL(saveSettingsRequested()));
 }
@@ -375,6 +373,7 @@ void MainWindow::extensionsInitialized()
     emit m_coreImpl->coreAboutToOpen();
     show();
     emit m_coreImpl->coreOpened();
+    m_autoSaveSessionTimer->start();
 }
 
 void MainWindow::closeEvent(QCloseEvent *event)