debian系统替换阿里源
deb http://mirrors.aliyun.com/debian/ stretch main contrib non-freedeb http://mirrors.aliyun.com/debian/ stretch-updates main contrib non-freedeb http://mirrors.aliyun.com/debian/ stretch-proposed-upd
deb http://mirrors.aliyun.com/debian/ stretch main contrib non-freedeb http://mirrors.aliyun.com/debian/ stretch-updates main contrib non-freedeb http://mirrors.aliyun.com/debian/ stretch-proposed-upd