title: Morris Donut chart no data issue
body: <p>I am trying to plot some data correctly with Morris Charts using Donut shape.</p>
  
  <pre><code>Morris.Donut({
          element: 'donut-chart-revenue',
          data: [],
        });
  </code></pre>
  
  <p>but since the data variable can sometimes be empty (new user , no enough data) the donut shape breaks and i'm having a void placeholder !</p>
  
  <p>How can i sort the problem or replace the placeholder with some text like "No enough data" ?</p>