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

ReactDOMComponent.Mixin = {
  /**
   * Generates root tag markup then recurses. This method has side effects and
   * is not idempotent.
   *
   * @internal
   * @param {ReactReconcileTransaction|ReactServerRenderingTransaction} transaction
   * @param {?ReactDOMComponent} the containing DOM component instance
   * @param {?object} info about the host container
   * @param {object} context
   * @return {string} The computed markup.
   */
  mountComponent: function(
    transaction,
    hostParent,
    hostContainerInfo,
    context
  ) {
    this._rootNodeID = globalIdCounter++;
    this._domID = hostContainerInfo._idCounter++;
    this._hostParent = hostParent;
    this._hostContainerInfo = hostContainerInfo;
    var props = this._currentElement.props;
    switch (this._tag) {
      case 'audio':
      case 'form':
      case 'iframe':
      case 'img':
      case 'link':
      case 'object':