Bug 337179

During .docx document sending to Outlook client Kmail loses atachment filename encoding.
This information was correct at the sent-mail folder but bad on receiver side, e.g.
sent-mail:
--nextPart2170179.eotn1eU03S
Content-Transfer-Encoding: 7Bit
Content-Type: text/plain; charset="utf-8"


--nextPart2170179.eotn1eU03S
Content-Disposition: attachment; filename="=?UTF-8?B?0KLQtdGB0YLQvtCy0YvQuSDQtNC+0LrRg9C80LXQvdGCLmRvY3g=?="
Content-Transfer-Encoding: base64
Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document; name="=?UTF-8?B?0KLQtdGB0YLQvtCy0YvQuSDQtNC+0LrRg9C80LXQvdGCLmRvY3g=?="

on receiver side:
--nextPart2170179.eotn1eU03S
Content-Transfer-Encoding: 7Bit
Content-Type: text/plain; charset="utf-8"


--nextPart2170179.eotn1eU03S
Content-Disposition: attachment; filename*=''%D0%A2%D0%B5%D1%81%D1%82%D0%BE%D0%B2%D1%8B%D0%B9%20%D0%B4%D0%BE%D0%BA%D1%83%D0%BC%D0%B5%D0%BD%D1%82%2Edocx
Content-Transfer-Encoding: base64
Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document; name*=''%D0%A2%D0%B5%D1%81%D1%82%D0%BE%D0%B2%D1%8B%D0%B9%20%D0%B4%D0%BE%D0%BA%D1%83%D0%BC%D0%B5%D0%BD%D1%82%2Edocx

and outlook could not recognize attachment filename.

Reproducible: Always