CI: Ensure firewalld is unmasked

Recent nodepool images are masking the firewalld service [1], but we
need it for host configure jobs.

[1] https://review.opendev.org/c/opendev/zuul-providers/+/967962

Change-Id: Ic72f2e3a262d6491da8bc39de19e23c3acbedf89
Signed-off-by: Pierre Riteau <[email protected]>

Author: priteau

playbooks/kayobe-overcloud-host-configure-base/pre.yml

@@ -43,3 +43,9 @@
       become: true
       loop: "{{ range(2, 8) | list }}"
       when: ansible_facts.os_family == 'Debian'
+
+    - name: Ensure firewalld is unmasked
+      ansible.builtin.systemd_service:
+        name: firewalld
+        masked: false
+      become: true