title: check if file exists in salt file system salt://
body: <p>I would like to check if a file exist in salt file system (salt://) and add an instruction depending on that. 
  I precise that I use gitfs as a mount point in the salt file system and don't use /srv directory.</p>
  
  <p>So more concretely I want to do something like that :</p>
  
  <pre><code>{% if salt['file.directory_exists']('salt://a_directory') %}
   file.recurse:
      - name: dest
      - source: salt://a_directory
      - template: jinja
  {% endif %}
  </code></pre>
  
  <p>but it seem not to work.</p>