core: fix Folder_cut to check relations of sub-objects

This `o` was an unused variable. The initial intention was probably
this.

product/ERP5/bootstrap/erp5_core/SkinTemplateItem/portal_skins/erp5_core/Folder_cut.py

@@ -9,8 +9,8 @@ Base_translateString = portal.Base_translateString
 def Object_hasRelation(obj):
   # Check if there is some related objets.
   result = 0
-  for o in obj.getIndexableChildValueList():
-    for related in obj.portal_categories.getRelatedValueList(obj):
+  for sub_obj in obj.getIndexableChildValueList():
+    for related in obj.portal_categories.getRelatedValueList(sub_obj):
       if related.getRelativeUrl().startswith(obj.getRelativeUrl()):
         continue
       elif related.getRelativeUrl().startswith('portal_simulation') :