title: mkvirtualenv gives permission denied error
body: <p>When running: 
      mkvirtualenv test</p>
  
  <p>I get following error:</p>
  
  <pre><code>  File "/usr/lib/python3/dist-packages/virtualenv.py", line 2378, in &lt;module&gt;
      main()
    File "/usr/lib/python3/dist-packages/virtualenv.py", line 830, in main
      symlink=options.symlink)
    File "/usr/lib/python3/dist-packages/virtualenv.py", line 999, in create_environment
      site_packages=site_packages, clear=clear, symlink=symlink))
    File "/usr/lib/python3/dist-packages/virtualenv.py", line 1198, in install_python
      mkdir(lib_dir)
    File "/usr/lib/python3/dist-packages/virtualenv.py", line 451, in mkdir
      os.makedirs(path)
    File "/usr/lib/python2.7/os.py", line 150, in makedirs
      makedirs(head, mode)
    File "/usr/lib/python2.7/os.py", line 150, in makedirs
      makedirs(head, mode)
    File "/usr/lib/python2.7/os.py", line 157, in makedirs
      mkdir(name, mode)
  OSError: [Errno 13] Permission denied: 'test'
  </code></pre>
  
  <p>Why is the 'test' virtual environment not created? I did try to chmode -R 777 the virtualenv folder, but that did not solve it. I  do have python 2.7 and 3.4 installed on Ubuntu 15.04 </p>