title: flake8 not picking up config file
body: <p>I have my <code>flake8</code> config file in <code>~/.config/flake8</code></p>
  
  <pre><code>[flake8]
  max-line-length = 100
  </code></pre>
  
  <p>However when I run <code>flake8</code> the config file is not picked up. I know that because i still get warnings over lines longer than 79 char.</p>
  
  <p>I'm on redhat, but the same happens on mac.</p>
  
  <p>I use pyenv. Global is 2.7.6 (not even sure this is relevant)</p>