If SELinux is enabled ensure we also have restorecon.
    
    We don't have a specific requires on the policycoreutils package. It
    gets pulled in as a dependency on the server anyway, but checking
    there is like a belt and suspenders.
    
    On the client we don't require SELinux at all. If SELinux is enabled
    however we need to set things up properly. This is provided by the
    policycoreutils package so fail if that isn't available.
    
    https://fedorahosted.org/freeipa/ticket/2368