Do not place debian.cnf when root user not touched

We used to overwrite /etc/mysql/debian.cnf file that is provided by
package when we were resetting root password for mariadb. That was
required as otherwise systemd couldn't manage service properly.
Now, when galera_root_user can be different then root, we don't need to
do this and can rely on defaults.

Change-Id: Ia8305121900d28aca28a80c6c9d6a664aec40214
Closes-Bug: #1979726

tasks/galera_server_post_install.yml

@@ -152,7 +152,7 @@
       dest: /etc/mysql/debian.cnf
       config_overrides: "{{ galera_debian_cnf_overrides }}"
       config_type: "ini"
-      condition: "{{ (ansible_facts['os_family'] | lower == 'debian') }}"
+      condition: "{{ (ansible_facts['os_family'] | lower == 'debian') and (galera_root_user == 'root') }}"
     - src: "client.my.cnf.j2"
       dest: "/root/.my.cnf"
       config_overrides: "{{ galera_client_my_cnf_overrides }}"