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

spyOn(console, 'error');
      ReactDOMServer.renderToString(<div class="paladin"/>);
      ReactDOMServer.renderToString(<input type="text" onclick="1"/>);
      expect(console.error.argsForCall.length).toBe(2);
      expect(
        console.error.argsForCall[0][0].replace(/\(.+?:\d+\)/g, '(**:*)')
      ).toBe(
        'Warning: Unknown DOM property class. Did you mean className? (**:*)'
      );
      expect(
        console.error.argsForCall[1][0].replace(/\(.+?:\d+\)/g, '(**:*)')
      ).toBe(
        'Warning: Unknown event handler property onclick. Did you mean ' +
        '`onClick`? (**:*)'
      );
    });
    it('gives source code refs for unknown prop warning for update render', function() {
      spyOn(console, 'error');
      var container = document.createElement('div');
      ReactDOMServer.renderToString(<div className="paladin" />, container);
      expect(console.error.argsForCall.length).toBe(0);
      ReactDOMServer.renderToString(<div class="paladin" />, container);
      expect(console.error.argsForCall.length).toBe(1);
      expect(
        console.error.argsForCall[0][0].replace(/\(.+?:\d+\)/g, '(**:*)')
      ).toBe(
        'Warning: Unknown DOM property class. Did you mean className? (**:*)'
      );
    });
    it('gives source code refs for unknown prop warning for exact elements ', function() {