[overcloud] allow to set SELinux state before overcloud deployment
[overcloud] allow to set SELinux state before overcloud deployment

use case: testing packages from source like openvswitch which violate
SELinux policy. In order not to wait for new a SELinux policy RPM and
to be able to test openvswitch from source, we can set SELinux
to permissive.

Change-Id: I2cf40c055e60cef8f4fafcf1fb83b86d2bc4dfa8

okolisny/InfraRed,redhat-openstack/infrared,okolisny/InfraRed,redhat-openstack/infrared,redhat-openstack/infrared,okolisny/InfraRed