Code review comment for lp:~jelmer/launchpad/sync-tbz2

Fixes support for syncing packages in the the version 3 source format (bug 225151).

This patch adds support for .orig.tar.bz2 files as well as multiple component orig tarballs in the script that syncs source packages from Debian. These new file formats are used by the new Debian source package format, v3.0.

This branch also refactors sync-source.py to use code from lp.soyuz.scripts.ftpmaster (well unit tested) rather its local copy (no tests). It also removes duplicate code for parsing dsc files from lp.soyuz.scripts.dak_utils in favor of the Dsc parser in debian_bundle.deb822.