Add selinux puppet module

The selinux puppet module makes it easy to change status of selinux
activation (enforcing/permissive/disabled) for CentOS/Red Hat.

Change-Id: I6e57ebbc6d78051021a2f4062edab09b92c6e03d
Reviewed-on: https://review.openstack.org/35542
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Reviewed-by: Khai Do <zaro0508@gmail.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins