Re: Bad objects error since upgrading GitHub servers to 1.6.1

As we do not know what version github used to run (or for that matter what
custom code it adds to 1.6.1), I guessed that the previous one was 1.6.0.6
and did some comparison.  The client side pack_object() learned to take
alternates on the server side into account to avoid pushing objects that
the target repository has through its alternates, so it is not totally
unexpected the client side changes its behaviour depending on what the
server does.

The only custom code we've written was a patch to git-daemon to map
pjhyett/github.git to a sharded location (eg.
/repositories/1/1e/df/a0/pjhyett/github.git) instead of the default.

The new alternates code in 1.6.1 sounds like that could be the issue.

-PJ