Usually, the "%h" format should result in an abbreviated sha1, but it
looks like getting it through `git archive' returns the full thing
rather than the truncated version. So avoid the substring for now, and
find out if it's a git bug or not.
Some mentions of svn/subversion are replaced with git, and some patterns
for paths to ignore include ".git*". (Note ".mailmap" not added, might
need to.)