title: TimePicker displays value 0 always in the default value
body: <p>I'm developing a component in React JS with <code>import TimePicker from 'rc-time-picker';</code></p>
  
  <p>The default values it's always 0.</p>
  
  <p>I have define a function like :</p>
  
  <pre><code>function getCurrentHours (){
    return moment().format('HH');
  }
  
  &lt;TimePicker 
      style={{ width: 50 }}
      defaultValue={getCurrentHours()}
      hideDisabledOptions
      disabledHours={getDisabledHours} /*horas que não podem ser selecionadas*/
      showSecond={false} 
      showMinute={false}
      {...rest}
      selected={this.state.selectedDate}
      onChange={this.handleChange}
  /&gt;
  </code></pre>
  
  <p>How to fix this? </p>