#i120072#, free local XMLPropertyHandler object to avoid leak

Patch by: Huang Chao
Review by: zhangjf

sw/source/filter/xml/xmlexpit.cxx

@@ -1016,6 +1016,8 @@ sal_Bool SvXMLExportItemMapper::QueryXMLValue(
                                                       rUnitConverter );
                 if( bOk )
                     aOut.append( sValue );
+
+                delete pWritingModeHandler;  // memory leak #i120072#
             }
         }
         break;