update pg_hba tasks

Allow execution of the "generate pg_hba.conf on Replica" task for RedHat-based systems, if the "postgresql_exists" variable is "true".

Allow to perform pg_hba tasks before executing the add_pgnode.yml playbook for cluster scaling:
ansible-playbook deploy_pgcluster.yml --tags pg_hba

roles/patroni/tasks/main.yml

@@ -827,6 +827,7 @@
         owner: postgres
         group: postgres
         mode: 0640
+      register: generate_pg_hba
       when: is_master == "true"
 
     - name: Prepare PostgreSQL | generate pg_hba.conf on Replica
@@ -836,8 +837,9 @@
         owner: postgres
         group: postgres
         mode: 0640
-      when: is_master != "true" and
-            postgresql_conf_dir != postgresql_data_dir
+      register: generate_pg_hba
+      when: (is_master != "true" and postgresql_conf_dir != postgresql_data_dir)
+            or postgresql_exists == "true"
 
     - name: Prepare PostgreSQL | reload for apply the pg_hba.conf
       become: true
@@ -846,6 +848,7 @@
       register: psql_reload_result
       changed_when: psql_reload_result.rc == 0
       failed_when: false  # exec pg_reload_conf on all running postgres (to re-run with --tag pg_hba).
+      when: generate_pg_hba is changed
   when: existing_pgcluster is not defined or not existing_pgcluster|bool
   tags: patroni, pg_hba, pg_hba_generate