roles/common: notify fail2ban after updating firewall

We should always restart fail2ban after updating the firewall. Also
note that the order of execution of handlers depends on how they are
defined in the handler config, not on the order they are listed in
the task's notify statement.

See: https://docs.ansible.com/ansible/latest/user_guide/playbooks_handlers.html

roles/common/handlers/main.yml

@@ -10,11 +10,14 @@
 - name: restart firewalld
   systemd: name=firewalld state=restarted
 
-- name: restart fail2ban
-  systemd: name=fail2ban state=restarted
-
 - name: reload systemd
   systemd: daemon_reload=yes
 
 - name: restart nftables
   systemd: name=nftables state=restarted
+
+# 2021-09-28: note to self to keep fail2ban at the end, as handlers are executed
+# in the order they are defined, not in the order they are listed in the task's
+# notify statement and we must restart fail2ban after updating the firewall.
+- name: restart fail2ban
+  systemd: name=fail2ban state=restarted