React 0.14.7: `<option value="">empty</option>` emits empty string on change
http://jsbin.com/pisita/10/edit?html,js,console,output
React 15.0.0-rc.1`<option value="">empty</option>` emits string with value "empty" on change
http://jsbin.com/bemaze/12/edit?html,js,console,output
This is because React 15.0.0-rc.1 cuts off `value=""` from option tag

'Decide between using a controlled or uncontrolled input ' +
          'element for the lifetime of the component. More info: https://fb.me/react-controlled-components',
          owner && owner.getName() || 'A component',
          props.type
        );
        didWarnControlledToUncontrolled = true;
      }
    }
    
    var checked = props.checked;
    if (checked != null) {
      DOMPropertyOperations.setValueForProperty(
        ReactDOMComponentTree.getNodeFromInstance(inst),
        'checked',
        checked || false
      );
    }
    var value = LinkedValueUtils.getValue(props);
    if (value != null) {
      
      
      DOMPropertyOperations.setValueForProperty(
        ReactDOMComponentTree.getNodeFromInstance(inst),
        'value',
        '' + value
      );
    }
  },
};
function _handleChange(event) {