解决php72的Headers and client library minor version dismatch问题

直接yum install php-mysqlnd 会报错：

执行以下命令可发现

php -i|grep Client

Client API library version => 5.6.51
Client API header version => 5.5.65-MariaDB
Client API version => 5.6.51

只需卸载已安装的连接工具并安装php72w对应版本mysqlnd即可：

yum remove php-mysql 
yum install php72w-mysqlnd

再次调用php -i|grep Client可发现：

Client API library version => mysqlnd 5.0.12-dev - 20150407 - $Id: 3591daad22de08524295e1bd073aceeff11e6579 $
Client API version => mysqlnd 5.0.12-dev - 20150407 - $Id: 3591daad22de08524295e1bd073aceeff11e6579 $

版本已保持一致.