Partially revert -lastsession fix

Change-Id: I965c8e51ca38b343e65764f77fe1d204ff793f23
Reviewed-on: http://codereview.qt.nokia.com/3411Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>

src/plugins/projectexplorer/projectexplorer.cpp

@@ -1318,10 +1318,10 @@ void ProjectExplorerPlugin::currentModeChanged(Core::IMode *mode, Core::IMode *o
 
 void ProjectExplorerPlugin::determineSessionToRestoreAtStartup()
 {
-    QStringList arguments = pluginSpec()->arguments();
     // Process command line arguments first:
-    if (arguments.contains("-lastsession"))
+    if (pluginSpec()->arguments.contains("-lastsession"))
         d->m_sessionToRestoreAtStartup = d->m_session->lastSession();
+    QStringList arguments = ExtensionSystem::PluginManager::instance()->arguments();
     if (d->m_sessionToRestoreAtStartup.isNull()) {
         QStringList sessions = d->m_session->sessions();
         // We have command line arguments, try to find a session in them