When `/etc/selinux/config' does not exist, although selinux has
already been disabled, the image creation will fail.
Change-Id: I9e4a9a006073fd3f708049407ef98f82c3f399d1
Having all security enabled is not always interesting, e.g. when
developing or testing new elements.
Change-Id: I828ecedc805ce4f89d60d185994eaa9c651d436a