title: git checkout <branchname> systematicaly modify files
body: <p>This is driving me crazy and I can't find why it's doing this...</p>
  
  <pre><code>git clone git@github.com:/my/working/repo.git
  --I don't do anything in the working copy--
  git status
  --no modification/no file to be commited--
  git checkout another_branch
  --I don't do anything in the working copy--
  git status
  modified: /some/file/that/I/touched.php
  modified: /some/file/that/I/touched2.php
  modified: /some/file/that/I/touched3.php
  </code></pre>
  
  <p>And when I do a git diff it shows only some line ending modifications.
  I see you coming... You're gonna tell me that I have to set autocrlf to false... Already tried that, and changes nothing...</p>
  
  <p>If anyone has an idea on how to fix this i'd be more than pleased...</p>
  
  <p>Thank you.</p>