* delegate default value handling to _baseGetReference

* this indirectly fix a site error on portal_property_sheets/view
  when a property had no reference

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@44209 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/id_as_reference.py

@@ -67,10 +67,10 @@ def IdAsReferenceMixin(suffix):
 
     security.declareProtected(Permissions.AccessContentsInformation,
                               'getReference')
-    def getReference(self, default=None):
+    def getReference(self, *args):
       id = self.id
       if id[suffix_index:] == suffix:
         return id[:suffix_index]
-      return self._baseGetReference(default=default)
+      return self._baseGetReference(*args)
 
   return IdAsReferenceMixin