title: Error while creating neutron client
body: <p>I am a newbie with openstack environment and i am trying my hands on with Openstack API. 
  I am getting following error while executing a basic script to list networks using neutron API. </p>
  
  <p>Script</p>
  
  <pre><code>#!/usr/bin/env python
  from neutronclient.v2_0 import client as neutronClient
  import os
  
  neutronConnection = neutronClient.Client(
      username=os.environ['OS_USERNAME'],
      password=os.environ['OS_PASSWORD'],
      tenant_name=os.environ['OS_TENANT_NAME'],
      auth_url=os.environ['OS_AUTH_URL']
      )
  print neutronConnection
  neutronConnection.format = 'json'
  neutronConnection.list_networks()
  </code></pre>
  
  <p>Error </p>
  
  <pre><code>    neutronConnection.list_networks()
    File "/usr/lib/python2.6/site-packages/neutronclient/v2_0/client.py", line 98, in with_params
      ret = self.function(instance, *args, **kwargs)
    File "/usr/lib/python2.6/site-packages/neutronclient/v2_0/client.py", line 339, in list_networks
      **_params)
    File "/usr/lib/python2.6/site-packages/neutronclient/v2_0/client.py", line 1334, in list
      for r in self._pagination(collection, path, **params):
    File "/usr/lib/python2.6/site-packages/neutronclient/v2_0/client.py", line 1347, in _pagination
      res = self.get(path, params=params)
    File "/usr/lib/python2.6/site-packages/neutronclient/v2_0/client.py", line 1320, in get
      headers=headers, params=params)
    File "/usr/lib/python2.6/site-packages/neutronclient/v2_0/client.py", line 1297, in retry_request
      headers=headers, params=params)
    File "/usr/lib/python2.6/site-packages/neutronclient/v2_0/client.py", line 1232, in do_request
      self.httpclient.authenticate_and_fetch_endpoint_url()
    File "/usr/lib/python2.6/site-packages/neutronclient/client.py", line 152, in authenticate_and_fetch_endpoint_url
      self.authenticate()
    File "/usr/lib/python2.6/site-packages/neutronclient/client.py", line 249, in authenticate
      self._authenticate_keystone()
    File "/usr/lib/python2.6/site-packages/neutronclient/client.py", line 228, in _authenticate_keystone
      allow_redirects=True)
    File "/usr/lib/python2.6/site-packages/neutronclient/client.py", line 138, in _cs_request
      raise exceptions.Unauthorized(message=body)
  neutronclient.common.exceptions.Unauthorized: {"error": {"message": "Could not find project, ESS.", "code": 401, "title": "Unauthorized"}}
  </code></pre>