title: pyenv local - can't set a Python version by its number despite the fact that it's installed
body: <p>Any suggestions on how you set the version of Python for pyenv?</p>
  
  <p>E.g.</p>
  
  <pre><code>$ python3
  Python 3.6.0 (v3.6.0:41df79263a11, Dec 22 2016, 17:23:13) 
  $ pyenv local
  pyenv: no local version configured for this directory
  $ pyenv local 3.6.0
  pyenv: version `3.6.0' not installed
  $ pyenv local v3.6.0:41df79263a11
  pyenv: version `v3.6.0' not installed
  </code></pre>