title: brew doctor says I have have uncommitted modifications to Homebrew but git status says "nothing to commit"
body: <p>I'm installing brew for the first time, and down to one error when I run brew doctor:</p>
  
  <pre><code>Warning: You have uncommitted modifications to Homebrew
  If this a surprise to you, then you should stash these modifications.
  Stashing returns Homebrew to a pristine state but can be undone
  should you later need to do so for some reason.
      cd /usr/local &amp;&amp; git stash
  </code></pre>
  
  <p>If I cd to /usr/local and run "git status" I get:</p>
  
  <pre><code>On branch master
  nothing to commit (working directory clean)
  </code></pre>
  
  <p>If I run: cd /usr/local &amp;&amp; git stash, I get:</p>
  
  <pre><code>No local changes to save
  </code></pre>
  
  <p>Should I ignore this warning? I'm on OSX 10.8.</p>