nodepool-base: Mask firewalld unit

Rocky9/10 in OpenDev seems to use firewalld instead of iptables.service

iptables.service enablement doesn't seem to work if firewalld.service
is enabled as well

Change-Id: I1d6feb0de26e2cf5ed75a619b81e97a6d66da090
Signed-off-by: Michal Nasiadka <mnasiadka@gmail.com>

dib-elements/nodepool-base/post-install.d/20-iptables

@@ -40,6 +40,8 @@ case "$DIB_INIT_SYSTEM" in
         # nothing to do
         ;;
     systemd)
+        # Make sure firewalld is masked and won't be started
+        systemctl mask firewalld.service
         if [[ "$DISTRO_NAME" == 'gentoo' ]] ; then
             for service in ${service_name}; do
                 systemctl enable "${service}-restore.service"