Comment 70 for bug 849416

i pinpointed the bug to a single line

Content-Type: multipart/mixed;
vs.
Content-Type: multipart/alternative;

the email is sent from a python code, and the attachment is visible both cases on gmail webclient.

Content-Type: multipart/alternative; --> not showing attachment
vs.
Content-Type: multipart/mixed; --> does show attachment

example eml file:
not showing attachment: http://pastebin.com/33cvj9Pi
showing attachment: http://pastebin.com/yjbgVK6w