title: Git svn clone produces empty directory
body: <p>I'm trying to clone the SVN repository at <a href="http://svn.openstreetmap.org/applications/editors/josm" rel="nofollow">http://svn.openstreetmap.org/applications/editors/josm</a> when I do a <code>svn co http://svn.openstreetmap.org/applications/editors/josm</code> it works fine but if I do a <code>git svn clone -s http://svn.openstreetmap.org/applications/editors/josm</code> it produces an  produces a josm directory with nothing but a .git directory in it. Is there something I'm missing? Here's the output of the command:</p>
  
  <pre><code>$ git svn clone -s http://svn.openstreetmap.org/applications/editors/josm
  WARNING: --prefix is not given, defaulting to empty prefix.
           This is probably not what you want! In order to stay compatible
           with regular remote-tracking refs, provide a prefix like
           --prefix=origin/ (remember the trailing slash), which will cause
           the SVN-tracking refs to be placed at refs/remotes/origin/*.
  NOTE: In Git v2.0, the default prefix will change from empty to 'origin/'.
  Initialized empty Git repository in /tmp/josm/.git/
  Using higher level of URL: http://svn.openstreetmap.org/applications/editors/josm =&gt; http://svn.openstreetmap.org
  W: Ignoring error from SVN, path probably does not exist: (160013): Filesystem has no item: '/!svn/rvr/100' path not found: Additional errors:: File not found: revision 100, path '/applications/editors/josm'
  W: Do not be alarmed at the above message git-svn is just searching aggressively for old history.
  This may take a while on large repositories
  
  $ cd josm; git reflog
  fatal: bad default revision 'HEAD'
  </code></pre>