Fix disabling of SELINUX

Per the [Redhat documentation](https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/ch-The_sysconfig_Directory.html#s2-sysconfig-selinux) /etc/sysconfig/selinux is a symlink to /etc/selinux/config. We only need to change /etc/selinux/config and future changes to /etc/sysconfig/selinux will NOT be seen by the system as it reads /etc/selinux/conf on startup.