When pushing, git/send would sometimes decide we had all the
objects that we'd need to update the remote, and would try
to pack and send the entire history of the repository. This
is because we only set the 'theirs' ref when we had the object.
If we didn't have the object, we would set a zero hash,
then when deciding if we needed to force, we would think
that we were updating a new branch and send everything,
which would fail to update the remote.
It's not fatal for someone else to push a branch
with objects that we don't have. We should deal
with it gracefully, and act as though it doesn't
exist.
We weren't giving all objects to the twixt() function, and
it was making bad life choices -- gambling, smoking, drinking,
and packing in too much data.
With more information, it doesn't do the last.
