don't hide 'type' builtin

use 'is' to compare with None


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@29971 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Tool/NotificationTool.py

@@ -146,9 +146,9 @@ def buildEmailMessage(from_url, to_url, msg=None,
 
     # try to guess the mime type
     if not attachment.has_key('mime_type'):
-      type, encoding = guess_type( attachment_name )
-      if type != None:
-        attachment['mime_type'] = type
+      mime_type, encoding = guess_type( attachment_name )
+      if mime_type is not None:
+        attachment['mime_type'] = mime_type
       else:
         attachment['mime_type'] = 'application/octet-stream'