title: git log --follow, the gitpython way
body: <p>I am trying to access the commit history of a single file as in:</p>
  
  <pre><code>git log --follow -- &lt;filename&gt;
  </code></pre>
  
  <p>I have to use <a href="https://github.com/gitpython-developers/GitPython">gitpython</a>, so what I am doing now is:</p>
  
  <pre><code>import git 
  g = git.Git('repo_dir') 
  hexshas = g.log('--pretty=%H','--follow','--',filename).split('\n') 
  </code></pre>
  
  <p>then I build commit objects:</p>
  
  <pre><code>repo = git.Repo('repo_dir')
  commits = [repo.rev_parse(c) for c in r]
  </code></pre>
  
  <p>Is there a way to do it in a more gitpython-ic way?
  I tried both <code>commit.iter_parents()</code> and <code>commit.iter_items()</code>, but they both rely on <code>git-rev-list</code>, so they don't have a <code>--follow</code> option.</p>