if the value is None, don't output "None" in the html

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@25818 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Form/EditorField.py

@@ -91,6 +91,8 @@ class EditorWidget(Widget.TextAreaWidget):
     """ 
       Render form in view only mode.
     """
+    if value is None:
+      value = ''
     return value
 
 EditorWidgetInstance = EditorWidget()