xCAT 更新root ssh key方法

流程如下：生成新的key，分发新key，替换所有节点key，替换xcat key

ssh-keygen //生成新的key命令为id_rsa1
pscp id_rsa1.pub all:/root/.ssh/authorized_keys
mv id_rsa id_rsa.old
mv id_rsa.pub id_rsa.pub.old
mv id_rsa1 id_rsa
mv id_rsa1.pub id_rsa.pub 
pscp id_rsa all:/root/.ssh/
pscp id_rsa.pub all:/root/.ssh/
cp /root/.ssh/id_rsa.pub /install/postscripts/_ssh/authorized_keys