title: Pip trying to remove setuptools while installing something else
body: <p>I'm installing from a Pip requirements file that looks like this:</p>
  
  <pre><code>Mezzanine==1.2.4
  # psycopg2==2.4.5
  South==0.7.6
  django-compressor==1.2
  
  mezzanine-mdown==0.1a3
  Pygments==1.5
  </code></pre>
  
  <p>which results in this error (<code>django-appconf</code> is a dependency of <code>django-compressor</code>):</p>
  
  <pre><code>[...]
    Running setup.py install for django-appconf
  
    Found existing installation: setuptools 0.6c11
      Uninstalling setuptools:
  Exception:
  Traceback (most recent call last):
    File "/home/adambrenecki/lib/python2.7/pip/basecommand.py", line 107, in main
      status = self.run(options, args)
    File "/home/adambrenecki/lib/python2.7/pip/commands/install.py", line 261, in run
      requirement_set.install(install_options, global_options)
    File "/home/adambrenecki/lib/python2.7/pip/req.py", line 1162, in install
      requirement.uninstall(auto_confirm=True)
    File "/home/adambrenecki/lib/python2.7/pip/req.py", line 495, in uninstall
      paths_to_remove.remove(auto_confirm)
    File "/home/adambrenecki/lib/python2.7/pip/req.py", line 1492, in remove
      renames(path, new_path)
    File "/home/adambrenecki/lib/python2.7/pip/util.py", line 273, in renames
      shutil.move(old, new)
    File "/usr/local/lib/python2.7/shutil.py", line 300, in move
      os.unlink(src)
  OSError: [Errno 13] Permission denied: '/usr/local/bin/easy_install'
  </code></pre>
  
  <p>The weird thing is, whenever I install <code>django-compressor</code> (or any of the others) individually, it doesn't do this. It's only when I use the requirements file.</p>
  
  <p>The full command I'm using to install is <code>pip-2.7 install --install-option="--install-scripts=/home/[username]/webapps/[appname]/bin" --install-option="--install-lib=/home/[username]/webapps/[appname]/lib/python2.7" -r requirements.txt</code>. I'm on one of WebFaction's servers, if that helps.</p>