title: How to modify commit messages when converting from SVN to Git?
body: <p>I'm currently mirroring an existing SVN repository on Github. For the initial clone I did this:</p>
  
  <pre><code>git svn --authors-prog=fixsvnauthors clone http://closure-compiler.googlecode.com/svn/
  </code></pre>
  
  <p>To update the repo every hour I do this:</p>
  
  <pre><code>git svn --authors-prog=fixsvnauthors rebase
  </code></pre>
  
  <p>The <code>fixsvnauthors</code> maps the SVN user names (E-Mail addresses) to Git usernames. My problem is now that this SVN repository seems to have a strange policy for commit messages. Most of them start with an empty line. Github doesn't like that at all. All commit message summaries are empty which is pretty annoying. </p>
  
  <p>So when there is a nice way to fix the authors during cloning maybe there is also a way to fix commit messages? I simply want to <strong><em>trim</em></strong> the commit messages so they are correctly read by Github. Couldn't find anything like this in the documentation of git-svn but maybe I missed something. So how can I do this?</p>