message: [bugfix] render is crashed while this.$vantMessages is undefined
diff: @@ -7,8 +7,10 @@ export default {
  const { name } = this.$options;
  const prefix = name ? camelize(name) + '.' : '';
  - if (process.env.NODE_ENV !== 'production' && !this.$vantMessages) {
  + if (!this.$vantMessages) {
  + if (process.env.NODE_ENV !== 'production') {
  console.warn('[Vant] Locale not correctly registered.');
  + }
  return () => '';
  }
  