backport SVN commit 1041420 by aacid:

do not accept new pixmap requests if we are shutting down

svn path=/branches/KDE/4.3/kdegraphics/okular/; revision=1065308

core/document.cpp

@@ -2207,7 +2207,7 @@ void Document::requestPixmaps( const QLinkedList< PixmapRequest * > & requests,
     if ( requests.isEmpty() )
         return;
 
-    if ( !d->m_generator )
+    if ( !d->m_generator || d->m_closingLoop )
     {
         // delete requests..
         QLinkedList< PixmapRequest * >::const_iterator rIt = requests.constBegin(), rEnd = requests.constEnd();