bug: update hook failure doesn't prevent local deletion of a branch

Hello,

I wanted to delete a branch (let's call it "deleted-branch") from my public repository. I ran this:

$ git push origin :deleted-branch
deleting 'refs/heads/deleted-branch'
 Also local refs/remotes/up/deleted-branch
*** Update hook: aborting
error: hooks/update exited with error code 1
error: hook declined to update refs/heads/deleted-branch
ng refs/heads/deleted-branch hook declined
error: failed to push to '/path/to/git/repo.git'

Coincidentally, my update hook happened to have a bug in it that prevented me from running the operation.

However, when I run the operation again...

$ git push origin :deleted-branch
deleting 'refs/heads/deleted-branch'
 Also local refs/remotes/up/deleted-branch
error: unlink(.git/refs/remotes/up/deleted-branch) failed: No such file or 
directory
error: Failed to delete

If the remote didn't get deleted, then it seems wrong that the local copy does get deleted.

Summary: when using git-push to delete a remote branch, and that deletion is 
disallowed by the update hook, the local tracking branch _is_ deleted.

Obviously, this isn't _that_ serious because it could be recovered again with a git-fetch; but it does make some scary looking errors.

Andy