QmlDesigner: crash fix

The subcomponent manager populates the item library.
This means the ItemLibraryView has to be properly
initialized before we call m_subComponentManager->update().

I added a helper function and call it from activateAutoSynchronization(),
after all views have been attached.

Change-Id: Ie802f93c7d0a76b42160d4a92e8448e900380b71
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>

src/plugins/qmldesigner/qmldesignerplugin.cpp

@@ -302,6 +302,7 @@ void QmlDesignerPlugin::activateAutoSynchronization()
         m_mainWidget->showErrorMessage(errors);
     }
 
+    currentDesignDocument()->updateSubcomponentManager();
 
     connect(currentDesignDocument()->rewriterView(),
             SIGNAL(errorsChanged(QList<RewriterView::Error>)),