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

var ReactDOMInput = {
  getHostProps: function(inst, props) {
    var value = LinkedValueUtils.getValue(props);
    var checked = LinkedValueUtils.getChecked(props);
    var hostProps = Object.assign({
      
      
      type: undefined,
    }, DisabledInputUtils.getHostProps(inst, props), {
      defaultChecked: undefined,
      defaultValue: undefined,
      value: value != null ? value : inst._wrapperState.initialValue,
      checked: checked != null ? checked : inst._wrapperState.initialChecked,
      onChange: inst._wrapperState.onChange,
    });
    return hostProps;
  },
  mountWrapper: function(inst, props) {
    if (__DEV__) {
      LinkedValueUtils.checkPropTypes(
        'input',
        props,
        inst._currentElement._owner
      );
      var owner = inst._currentElement._owner;
      if (props.valueLink !== undefined && !didWarnValueLink) {
        warning(
          false,
          '`valueLink` prop on `input` is deprecated; set `value` and `onChange` instead.'
        );