Log Message:
Update amavisd-new to 2.6.1.
Based on maintainer update request in PR 39196.

There are a lot of changes and some incompatabilities with 2.5.3
(current version in pkgsrc) particularly as respects SQL schema.
Consult vendor's releases notes for more detail:
    http://www.ijs.si/software/amavisd/release-notes.txt