Delete the oldModel even if the new doc has no toc

BUGS: 313146

ui/toc.cpp

@@ -73,14 +73,6 @@ void TOC::notifySetup( const QVector< Okular::Page * > & /*pages*/, int setupFla
     // request synopsis description (is a dom tree)
     const Okular::DocumentSynopsis * syn = m_document->documentSynopsis();
 
-    // if not present, disable the contents tab
-    if ( !syn )
-    {
-        emit hasTOC( false );
-        return;
-    }
-
-    // else populate the listview and enable the tab
     m_model->fill( syn );
     emit hasTOC( !m_model->isEmpty() );
 }

ui/tocmodel.cpp

@@ -266,8 +266,12 @@ static QModelIndex indexForIndex( const QModelIndex &oldModelIndex, QAbstractIte
 
 void TOCModel::fill( const Okular::DocumentSynopsis *toc )
 {
-    if ( !toc )
+    if ( !toc ) {
+        delete d->m_oldModel;
+        d->m_oldModel = 0;
+        d->m_oldTocExpandedIndexes.clear();
         return;
+    }
 
     clear();
     emit layoutAboutToBeChanged();