display (None) for empty item.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@33525 20353a03-c40f-0410-a6d1-a30d3c3de9de

bt5/erp5_simulation/SkinTemplateItem/portal_skins/erp5_simulation/SolverDecision_getDeliverySolverList.xml

@@ -54,10 +54,10 @@
         <item>
             <key> <string>_body</string> </key>
             <value> <string>try:\n
-  return [(\'\', \'\')] + [x for x in context.getPortalObject().portal_solvers.getDeliverySolverTranslatedItemList() \\\n
+  return [(\'(None)\', \'\')] + [x for x in context.getPortalObject().portal_solvers.getDeliverySolverTranslatedItemList() \\\n
       if x[1] in context.getSolverValue().getDeliverySolverList()]\n
 except AttributeError:\n
-  return [(\'\', \'\')]\n
+  return [(\'(None)\', \'\')]\n
 </string> </value>
         </item>
         <item>