SAK-27978 Use service name in List-ID header.

Uses localhost in the List-ID headers means it's not possible to tell apart emails from different Sakai services if the mailing list name is the same.

git-svn-id: https://source.sakaiproject.org/svn/mailarchive/trunk@314218 66ffb92e-73f9-0310-93c1-f5514f145a0a