fix Unhandled Rejection https://travis-ci.org/wechaty/wechaty/jobs/176334651#L1717
fix Unhandled Rejection https://travis-ci.org/wechaty/wechaty/jobs/176334651#L1717

wechaty/wechaty,Chatie/wechaty,lijiarui/wechaty,zixia/wechaty,wechaty/wechaty,mukaiu/wechaty,Chatie/wechaty,binsee/wechaty,binsee/wechaty,mukaiu/wechaty,binsee/wechaty,zixia/wechaty,mukaiu/wechaty,Chatie/wechaty,wechaty/wechaty,lijiarui/wechaty