add missing imports.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@25402 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Tool/NotificationTool.py

@@ -31,6 +31,8 @@ from Products.CMFCore.utils import getToolByName
 from Products.ERP5Type.Tool.BaseTool import BaseTool
 from Products.ERP5Type import Permissions
 from Products.ERP5 import _dtmldir
+from Products.ERP5.Document.Document import ConversionError
+from Products.ERP5.Document.EmailDocument import MimeTypeException
 
 from mimetypes import guess_type
 from email.MIMEMultipart import MIMEMultipart