title: Force git cherry-picks to update untracked files from nested repositories
body: <p>I'm currently working with a repository that has recently been broken up for the sake of close-sourcing - modules have been moved to their own repository away from the 'main' one.</p>
  
  <pre><code>panel/
      file.a
      file.b
      module1/ [untracked by panel repository, instead tracked in own repository now]
          templates/
              base.html
              ...
          views.py
  </code></pre>
  
  <p>However, there is still work that was committed before this break-up, when the <code>module1</code> repository was still part of <code>panel</code>. My issue is working with the commits from before and after this break-up - I'm currently trying to <code>cherry-pick</code> a commit with changes to files in both <code>panel</code> and <code>module1</code>, a commit that was created when both repositories were part of <code>panel</code>. (No directory structure has changed, only <code>git</code>'s view of the repositories)</p>
  
  <p>When I cherry pick while in the main repository's directory:</p>
  
  <pre><code>nasonfish@nasonfish ~/P/P/p/panel2&gt; git cherry-pick 8b7316d1ebff49e95a7971f88e669f50d9cbbf86
  error: refusing to lose untracked file at 'panel/module1/views.py'
  error: refusing to lose untracked file at 'panel/module1/templates/module1/view-hdr.html'
  error: refusing to lose untracked file at 'panel/module1/templates/module1/view-base.html'
  error: refusing to lose untracked file at 'panel/module1/templates/module1/base.html'
  error: could not apply 8b7316d... mybranch: This is my commit
  hint: after resolving the conflicts, mark the corrected paths
  hint: with 'git add &lt;paths&gt;' or 'git rm &lt;paths&gt;'
  hint: and commit the result with 'git commit'
  </code></pre>
  
  <p>I can see that I'm not looking to remove or add the files in the repository to the main repository because that just undoes the separation and combines the repositories - but I'm trying to make the <code>cherry-pick</code> apply that commit to the files in both the base and child repository without merging the two. So, <strong>is there a way to force git to act like the files in a separate nested repository are part of the main repository in some way that allows cherry-picking commits from before the repositories were separated?</strong></p>