CI: Set selinux_state to disabled for ci-builder environment

Without this it fails during seed host configuration because SELinux is disabled.

Author: markgoddard

etc/kayobe/environments/ci-builder/globals.yml

@@ -12,4 +12,4 @@ os_distribution: "{{ lookup('pipe', '. /etc/os-release && echo $ID') | trim }}"
 # SELinux.
 
 # Avoid a reboot.
-selinux_do_reboot: false
+selinux_state: disabled