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

this.updateTextContent('' + nextContent);
        if (__DEV__) {
          setContentChildForInstrumentation.call(this, nextContent);
        }
      }
    } else if (nextHtml != null) {
      if (lastHtml !== nextHtml) {
        this.updateMarkup('' + nextHtml);
      }
      if (__DEV__) {
        ReactInstrumentation.debugTool.onSetChildren(this._debugID, []);
      }
    } else if (nextChildren != null) {
      if (__DEV__) {
        setContentChildForInstrumentation.call(this, null);
      }
      this.updateChildren(nextChildren, transaction, context);
    }
  },
  getHostNode: function() {
    return getNode(this);
  },
  /**
   * Destroys all event registrations for this instance. Does not remove from
   * the DOM. That must be done by the parent.
   *
   * @internal
   */
  unmountComponent: function(safely) {
    switch (this._tag) {