Fix accessibility ancestor tree for folders panel

This is a followup to 549fad2dae.
That previous commit made sure that the accessibility tree for
Dolphin's main view was complete even though the view had no
parent by explicitly setting an accessible parent.

The folders panel also has a view though and that previous commit
did not contain an explicit call to also set an accessible parent
for it. This commit rectifies that.

Fixes a sanity check & crash in the debug build.
Belongs to Dolphin issue #47.

src/panels/folders/folderspanel.cpp

@@ -161,6 +161,9 @@ void FoldersPanel::showEvent(QShowEvent *event)
         connect(m_controller, &KItemListController::itemDropEvent, this, &FoldersPanel::slotItemDropEvent);
 
         KItemListContainer *container = new KItemListContainer(m_controller, this);
+#ifndef QT_NO_ACCESSIBILITY
+        view->setAccessibleParentsObject(container);
+#endif
         container->setEnabledFrame(false);
 
         QVBoxLayout *layout = new QVBoxLayout(this);