删除Mysql ：
删除mysql前 先删除一下 /var/lib/mysql 还有 /etc/mysql
->sudo rm /var/lib/mysql/-R
-> sudo rm /etc/mysql/-R
-> sudo apt-getautoremove mysql*--purge
-> sudo apt-getremove apparmor
-> ssudo apt-getinstall mysql-servermysql-common
http://www.jianshu.com/p/4646a60637a1
http://www.jianshu.com/p/8252f1e41d50
