title: gitolite disallow access for directory on master branch but not on user branch
body: <p>Consider the following repo:</p>
  
  <p>REPO/src/A/</p>
  
  <p>REPO/src/B/</p>
  
  <p>Is it possible by having only 1 repo to implement the following restrictions?</p>
  
  <ol>
  <li>On master branch, allow full access to maintainers role</li>
  <li>On master branch, disallow access to A but allow for B to contributors role.</li>
  <li>On personal branches, allow full access to A and B to creators.</li>
  </ol>