add missing empty line at the end

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@16506 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/EmailDocument.py

@@ -424,3 +424,4 @@ class EmailDocument(File, TextDocument):
 ## Compatibility layer
 #from Products.ERP5Type import Document
 #Document.MailMessage = EmailDocument
+