title: git --git-dir not working as expected
body: <p>I am trying to run git from a different directory than I am in. So for example if I am in:</p>
  
  <pre><code>cd /home/domain/
  git status &lt;&lt; runs perfect ie
  # On branch master
  # Your branch is ahead of 'origin/master' by 6 commits.
  </code></pre>
  
  <p>So now I want to run this command from a different directory using the <code>--git-dir</code> option.</p>
  
  <p>So lets say I'm in <code>root/</code> and try this:</p>
  
  <pre><code>git --git-dir="/home/domain/" status
  ## Error 
  fatal: Not a git repository: '/home/domain/'
  </code></pre>
  
  <p>I've also tried to include the <code>.git</code> folder i.e.</p>
  
  <pre><code>git --git-dir="/home/domain/.git/" status
  </code></pre>
  
  <p>But this looks like it's trying to run git from the root, i.e. deleting everything from my domain folder and adding everything in root.</p>
  
  <p>Hope someone can advise on what I'm doing wrong.</p>