Sometimes, a sysadmin might outright delete the SELinux rpms and
delete the configuration. This causes the selinux module to fail
with
```
IOError: [Errno 2] No such file or directory: '/etc/selinux/config'\n",
"module_stdout": "", "msg": "MODULE FAILURE"}
```
This simply checks that /etc/selinux/config exists before we try
to set it Permissive.
Update from feedback
22efbd0153