Remove useless "using" in LibXSLTTransformer (filter)

Change-Id: I13f1ebd8a0f8d2ff0384cccb1f7a161f4af668f4
Reviewed-on: https://gerrit.libreoffice.org/46187Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>

filter/source/xsltfilter/LibXSLTTransformer.hxx

@@ -40,7 +40,6 @@ using namespace ::com::sun::star::beans;
 using namespace ::com::sun::star::io;
 using namespace ::com::sun::star::uno;
 
-using ::std::list;
 using ::std::map;
 
 #define EXT_MODULE_OLE_URI "http://libreoffice.org/2011/xslt/ole"