Comment 12 for bug 30225

Testing this on staging shows that the fix isn't correct. The wrong mime parts are being picked up when sending an attachment via email.

 * Attachment added via the web interface:
    https://bugs.staging.launchpad.net/launchpad/+bug/192784/comments/3

 * Attachment added via the email interface:
    https://bugs.staging.launchpad.net/launchpad/+bug/192784/comments/2
    Notice how the attachment is displayed as the comment text, and instead of the attachment the file looks like some kind of text-encoded binary.