title: get_posts - orderby desc wrong order
body: <p>In my WordPress plugin I am getting posts using the following:</p>
  
  <pre><code>$args = array(
       'post_type' =&gt; 'wpplugin_pp_order',
       'posts_per_page' =&gt; -1,
       'order' =&gt; 'ASC',
       'orderby' =&gt; 'ID'
  );
  
  $posts = get_posts($args);
  </code></pre>
  
  <p>The problem is the result is returning like so for the post_id:</p>
  
  <pre><code>3000
  3001
  3002
  3003
  2999
  2998
  </code></pre>
  
  <p>How can I put the result the correct order?</p>