title: Python Version 2.7.6. psutil version 2.1.3 - AttributeError: 'module' object has no attribute 'users'
body: <p>I am running UBUNTU 14.04. Python version is 2.7.6 and psutil version is 2.1.3</p>
  
  <p>I import psutil and then call one of the following only to get errors.</p>
  
  <pre><code>    import psutil
      psutil.users()
      psutil.pids()
      psutil.cpu_times()
  </code></pre>
  
  <p>AttributeError: 'module' object has no attribute 'users'</p>
  
  <p>AttributeError: 'module' object has no attribute 'pids'</p>
  
  <p>AttributeError: 'module' object has no attribute 'boot_time'</p>
  
  <p>I <strong>do not</strong> have this issue with psutil.cpu_percent() and psutil.cpu_times()</p>