Help to enable/disable SELinux on the host.

def set_selinux(self, state):
        """Help to enable/disable SELinux on the host.
        """
        allowed_states = ('enforcing', 'permissive', 'disabled')
        if state not in allowed_states:
            raise Exception
        self.run('setenforce %s' % state)
        self.create_file('/etc/sysconfig/selinux',
                         'SELINUX=%s\nSELINUXTYPE=targeted\n' % state)