title: JUPYTER_PATH in environment variables not working
body: <p>I am trying to update <code>JUPYTER_PATH</code> for Jupyter notebook. I set the environment variables following <a href="http://jupyter.readthedocs.io/en/latest/projects/jupyter-directories.html" rel="nofollow noreferrer">the jupyter documentation</a> but still <code>jupyter contrib nbextension install --user</code>, for example, installed under <code>C:\Users\username\AppData\nbextensions</code> instead of <code>C:\somedir\AppData\Roaming\jupyter\nbextensions</code>. </p>
  
  <p>Added these to my environment variables.</p>
  
  <pre><code>JUPYTER_CONFIG_DIR=C:\somedir\.jupyter
  JUPYTER_PATH=C:\somedir\AppData\Roaming\jupyter
  JUPYTER_RUNTIME_DIR=C:\somedir\AppData\Roaming\jupyter
  </code></pre>
  
  <p><code>jupyter --path</code> shows</p>
  
  <pre><code>PS C:\somedir\&gt; jupyter --path
  config:
      C:\somedir\.jupyter
      C:\anaconda\python27\win64\431\etc\jupyter
      C:\ProgramData\jupyter
  data:
      C:\somedir\AppData\Roaming\jupyter
      C:\Users\username\AppData\Roaming\jupyter
      C:\anaconda\python27\win64\431\share\jupyter
      C:\ProgramData\jupyter
  runtime:
      C:\somedir\AppData\Roaming\jupyter
  </code></pre>
  
  <p><code>jupyter --data-dir</code> shows</p>
  
  <pre><code>jupyter --data-dir
  C:\Users\username\AppData\Roaming\jupyter
  </code></pre>
  
  <p>I think <code>C:\Users\username\AppData\Roaming\jupyter</code> needs to be removed but nor sure how. Can you please help?</p>