warning: remote HEAD refers to nonexistent ref, unable to checkout.

I try to clone the repo and get this:

$ git clone http://git.drupal.org/sandbox/jelles/1193994.git clientside_validation_example
Cloning into clientside_validation_example...
remote: Counting objects: 132, done.
remote: Compressing objects: 100% (132/132), done.
Receiving objects: 28% (37/132) d 0 (delta 0)
Receiving objects: 100% (132/132), 27.81 KiB, done.
Resolving deltas: 100% (91/91), done.
warning: remote HEAD refers to nonexistent ref, unable to checkout.

Oh yes, doing this gives the same result:
$ git clone git://git.drupal.org/sandbox/jelles/1193994.git clientside_validation_example

I do a Google search and find this:
http://stackoverflow.com/questions/8403792/git-behind-proxy-remote-head-...