Ubuntu使用国内源出现Hash Sum mismatch错误的解决

　　deb http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse

　　deb http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse

　　deb http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse

　　deb http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse

　　deb http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse

　　deb-src http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse

　　deb-src http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse

　　deb-src http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse

　　deb-src http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse

　　deb-src http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse