[Newbie] How to *actually* get rid of remote tracking branch?

Hello,

I want to get rid of origin/pu remote tracking branch. What do I do? I RTFM git-branch. What does it suggest?

git branch -d -r origin/pu

So far so good. However, it doesn't seem to work in practice:

$ git --version
git version 1.5.3.4
$ git remote show origin
* remote origin
  URL: git://git.kernel.org/pub/scm/git/git.git
  Remote branch(es) merged with 'git pull' while on branch master
    master
  Tracked remote branches
    html maint man master next pu todo
$ git branch -d -r origin/pu
Deleted remote branch origin/pu.
$ git remote show origin
* remote origin
  URL: git://git.kernel.org/pub/scm/git/git.git
  Remote branch(es) merged with 'git pull' while on branch master
    master
  New remote branches (next fetch will store in remotes/origin)
    pu
  ^^^^^^^^^^^^^^^^^^^ What???  
  Tracked remote branches
    html maint man master next todo
$ git fetch
remote: Generating pack...
remote: Done counting 422 objects.
Result has 281 objects.
remote: Deltifying 281 objects...
remote:  100% (281/281) done
Indexing 281 objects...
remote: Total 281 (delta 206), reused 255 (delta 181)
 100% (281/281) done
Resolving 206 deltas...
 100% (206/206) done
63 objects were added to complete this thin pack.
* refs/remotes/origin/pu: storing branch 'pu' of git://git.kernel.org/pub/scm/git/git
  commit: fc07419
$ git remote show origin
* remote origin
  URL: git://git.kernel.org/pub/scm/git/git.git
  Remote branch(es) merged with 'git pull' while on branch master
    master
  Tracked remote branches
    html maint man master next pu todo
$

... and I get those origin/pu back?!

What do I do wrong?