error: refs/remotes/origin/HEAD points nowhere!

Hi,

Very annoying error "error: refs/remotes/origin/HEAD points nowhere!" keeps popping up almost all the time after user has removed remote repository "origin". Here's a kind of real-life example:

I have cloned some remote repository:

  git clone git://project/project.git

After a while I start tracking some other remote repository. I do this:

  git remote add ng git://project-ng/project.git

Then I do "git fetch ng" and probably also "git checkout --track -b master-ng ng/master". Then I find the old "origin" useless to me so I remove it with "git remote rm origin".

It seems that refs/remotes/origin/HEAD is still left in my repository and hence I keep getting these annoying error messages all the time. Well, I know how to delete this file, but I believe that git should have deleted it when I called "git remote rm origin". Am I right? What is the purpose of this refs/remotes/origin/HEAD in the first place?

Anyway, thank you guys for this excellent tool and VCS/SCM system. Generally git is really joy to use and very powerful. Thanks.