packaging: setup: handle selinux  disabled

In engine-setup restored previous behavior, exiting if selinux is disabled.
In engine-setup-2 disable apache/selinux plugin if selinux is disabled.

Bug-Url: https://bugzilla.redhat.com/979763
Change-Id: I4242c7aedd805f6d7e4ffcc7dc6dd77a31c63dee
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>