Add upstream patch to fix a filtering bug in KMail.

Despite what the patch's commit message says, this is actually a fix for
https://bugs.kde.org/show_bug.cgi?id=340015, which is part of 4.14.3. It
allows filtering based on the "List-Id" header to work again.


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@372525 35697150-7ecd-e111-bb59-0022644237b5