tdf#92434 - dispose the table contents.

fix issue from: 6d0c8912

Change-Id: Ia5b7bb91c366ecbbb3111d6f5239d5360640ca2d
Reviewed-on: https://gerrit.libreoffice.org/16893Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Michael Meeks <michael.meeks@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/16895Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>

dbaccess/source/ui/querydesign/JoinTableView.cxx

@@ -1537,7 +1537,7 @@ void OJoinTableView::clearLayoutInformation()
     {
         if ( aIter->second )
             aIter->second->clearListBox();
-        aIter->second = NULL;
+        aIter->second.disposeAndClear();
     }
 
     m_aTableMap.clear();