Recovery after interrupted repack

Hi,

I interrupted git repack -a -f -d and now most commands say "fatal:
bad object HEAD".  Additionally an attempt to run git repack again
says a bunch of "error: refs/heads/foo does not point to a valid
object!" messages.

git fsck prints a huge list of "missing blob <sha-1>" lines.

I'm using a Cygwin build of git 1.7.5.1 (I also have a build of the
latest master available).

-- 
Hannu