title: Table columns name does not update on model change
body: <p>I create a table:</p>
  
  <pre><code>oTable.setModel(new sap.ui.model.json.JSONModel(oData));
          oTable.bindAggregation("items", "/items", new sap.m.ColumnListItem({
              cells: oData.cols.map(function (colname) {
                  return new sap.m.Label({ text: "{" + colname + "}" });
              })
          }));
  </code></pre>
  
  <p>Then I want to change the model (it contain rows AND cols):</p>
  
  <pre><code>oTable.setModel(new sap.ui.model.json.JSONModel(NEWoData));
      model =oTable.getModel();
      model.refresh();
  </code></pre>
  
  <p>But after refresh I see the new data(:D) but the old cols name!</p>