title: Git create patch for unpushed changes in other branch without checkout/switch
body: <p>I need to create backup for all committed(but not pushed) changes in other branch.</p>
  <p>I have 3 branches</p>
  <pre><code>C:\develop\V1001-git&gt;git branch
  * V1900
    V2000
    v2001
  </code></pre>
  <p>I have multiple branches in my repository. Now when I do <code>git format-patch origin/V1900</code> then I get the patches created for my committed but not pushed changes,
  but when I try to do it for other branch without switching to that branch for example</p>
  <p><code>git format-patch origin/V2000</code></p>
  <p>It starts creating patches for all the changes in the branch including the pushed one, which I dont want. I just want the committed but not pushed changes. Could you please help me with some ideas?</p>