title: svn: reverting to previous version
body: <p>I mistakenly committed the wrong change to file, for a simplified example's sake let's call it foo.txt:</p>
  
  <p>foo.txt, rev 300 (correct):</p>
  
  <pre><code> E = mc^2
  </code></pre>
  
  <p>foo.txt, rev 301 (incorrect):</p>
  
  <pre><code> E = mc^3
  </code></pre>
  
  <p>How do I re-commit rev 300 to the next commit? If I update foo.txt to rev 300, I get the right file but its status is correct &amp; doesn't require being committed.</p>
  
  <p><strong>NOTE:</strong> It's only foo.txt that I want to revert. The other revisions in rev 301 are important and I need to keep them.</p>