Code review comment for lp:~wgrant/launchpad/distroseries-source-format-selection

This is hopefully the last of my Debian source format 3.0 branches. It is a pretty simple extension and testing of existing code.

The two new formats are:

 - 3.0 (native): Like 1.0's native variant, but with bz2 compression permitted on the tarball.
 - 3.0 (quilt): Replaces 1.0's non-native variant. Requires an orig.tar.(gz|bz2), a debian.tar.(gz|bz2) (replacing 1.0's diff.gz), and at most one orig-$COMPONENT.tar.(gz|bz2) for each COMPONENT.

determine_source_file_type is extended to identify bz2 compression, debian tarballs, and component orig tarballs. All checks to allow duplicated ORIG_TARBALLS are extended to also permit COMPONENT_ORIG_TARBALLs, as they should be treated identically.

There are pretty simple additional checks in NascentUpload. Additional file type counters are added, as is one for bz2 compression. Compression and new file checks are added to the 1.0 section, as are fairly obvious new 3.0 (quilt) and 3.0 (native) sections.

A few new test source packages are required. I also convinced the 'absolutely-anything' upload policy to permit PPA uploads, since I needed to test with an unsigned PPA upload. I haven't tested all filetype-related rejection cases (the old code did not either), since that would require constructing several more bad source packages.