title: git submodules - how to undo git submodule update --init
body: <p>I have a git project with several submodules within.
  Between now and a year ago several submodules have moved - even some of the same have been moved a directory level down.  Another one moved from one URL to another and location location. Git does not take such changes kindly :)</p>
  <p>When I have my git and have run <code>git submodule update --init</code> - then I cannot run</p>
  <pre><code>$ git checkout OLDSHA
  fatal: not a git repository: sub/depdir/../../.git/modules/sub/depdir
  </code></pre>
  <p>or I get</p>
  <pre><code>fatal: could not get a repository handle for submodule 'sub/depdir'
  </code></pre>
  <p>If I clone the git from scratch, run <code>git checkout OLDSHA</code> - AND THEN <code>git submodule update --init</code>, no problems.</p>
  <p><strong>Then my question:</strong></p>
  <ul>
  <li>Is there a way to undo <code>git submodule update --init</code> which essentially brings me back to what I get after <code>git clone PROJECT &amp;&amp; cd project &amp;&amp; git checkout OLDSHA</code></li>
  </ul>
  <p>Note; this is NOT about getting rid of my submodules. The problem is to enable my e.g. to run git bisect across these changes more effetively without having to re-clone from scratch.</p>