erp5_core: ERP5Site_updateTranslationTable fix a condiction problem.

product/ERP5/bootstrap/erp5_core/SkinTemplateItem/portal_skins/erp5_core/ERP5Site_updateTranslationTable.xml

@@ -97,7 +97,7 @@ for portal_type in portal_type_list:\n
 \n
           # translate state title as well\n
           state_title = state.getTitle()\n
-          if state_title not in [None, \'\']:\n
+          if state_title is not None and state_title != \'\':\n
             state_var_title = \'%s_title\' % state_var\n
             msg_id = getMessageIdWithContext(state_title, \'state\', wf_id)\n
             translated_message = context.Localizer.erp5_ui.gettext(msg_id, default=\'\', lang=lang).encode(\'utf-8\')\n