title: jstree showing all nodes if search string didn't match any node
body: <p>I'm rendering jstree with following config</p>
  
  <pre><code>$('#deliverables').jstree({
      'core': {
          'data': data
      },
      'search': {
          'case_insensitive': true,
          'show_only_matches' : true
      },
      'plugins': ['search']
  });
  
  $('#deliverable_search').keyup(function(){
      $('#deliverables').jstree('search', $(this).val());
  });
  </code></pre>
  
  <p>With this config, jstree showing only matched nodes if the search text has found atleast one node. But jstree showing all the nodes if the search text not matching with any node. I found this a bit strange. Am i missing something here?</p>
  
  <p><a href="https://jsfiddle.net/t9fe58rt/1/">https://jsfiddle.net/t9fe58rt/1/</a> link for your reference.</p>