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

radioGroup: 0,
    readOnly: HAS_BOOLEAN_VALUE,
    rel: 0,
    required: HAS_BOOLEAN_VALUE,
    reversed: HAS_BOOLEAN_VALUE,
    role: 0,
    rows: HAS_POSITIVE_NUMERIC_VALUE,
    rowSpan: HAS_NUMERIC_VALUE,
    sandbox: 0,
    scope: 0,
    scoped: HAS_BOOLEAN_VALUE,
    scrolling: 0,
    seamless: HAS_BOOLEAN_VALUE,
    selected: MUST_USE_PROPERTY | HAS_BOOLEAN_VALUE,
    shape: 0,
    size: HAS_POSITIVE_NUMERIC_VALUE,
    sizes: 0,
    span: HAS_POSITIVE_NUMERIC_VALUE,
    spellCheck: 0,
    src: 0,
    srcDoc: 0,
    srcLang: 0,
    srcSet: 0,
    start: HAS_NUMERIC_VALUE,
    step: 0,
    style: 0,
    summary: 0,
    tabIndex: 0,
    target: 0,
    title: 0,