Comment 6 for bug 173096

Unfortunately, 'AddEncoding x-gzip .txt.gz' doesn't work - I can only
assume apache is doing something like url.split(".")[-1] and matching
on that for the extension argument.

Obviously, we should do the non-immediate fix of having the librarian
send the right Content-Encoding itself, but in the mean time someone else
needs to make the call of whether we break build logs for Ubuntu but
fix tar.gz downloads for everyone.