Mail multiparts are included in search results, even if mail is excluded

Mail multiparts are not properly handled by Confluence. They are seen has attachements.

The consequences are the following:

• On the search screen, I cannot totally excluded search from mails (search on all content, no mail): The result still shows unnamed-0, unamed-1 results, which are parts of mail (not real attachment, multipart content).

• On the result screen, their is a direct link to the attachement. It should be a link to the mail (with the mail title and not unamed-0). This is text and is usually shown inline in most mail readers. Replaced by CONF-12543