title: Git submodule to track remote branch
body: <p>I'm trying to use git submodules for aggregating 10+ repositories into one structure for easy development.</p>
  
  <p>It is supposed to clone the module and checkout a branch.
  Instead, the module is checked out in detached head mode.</p>
  
  <pre><code>git clone git@github.com:org/global-repository.git
  git submodule update —init
  cd config-framework
  git status
  
  $git status
  #HEAD detached at b932ab5
  nothing to commit, working directory clean
  </code></pre>
  
  <p>gitmodules files seems to be okay</p>
  
  <pre><code>$cat .gitmodules 
  [submodule "config-framework"]
          path = config-framework
          url = git@github.com:org/config-framework.git
          branch = MY_BRANCH
  </code></pre>
  
  <p>We want the MY_BRANCH branch to be checked out by default, rather than detached head.
  How do we achieve that?</p>