check if there is already permission on manage_setLocaLPermissions

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@1167 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/Base.py

@@ -1295,6 +1295,7 @@ class Base( CopyContainer, PortalContent, Base18, ActiveObject, ERP5PropertyMana
     """
     permission_name = pname(permission)
     if local_permission_list is None:
+      if hasattr(self,permission_name):
         delattr(self,permission_name)
     else:
       if type(local_permission_list) is type('a'):