Revert "Generate backend TLS for all overcloud"

This reverts commit 58a46b8.

Author: seunghun1ee

etc/kayobe/ansible/vault-generate-backend-tls.yml

@@ -2,7 +2,7 @@
 # Required for uri module to work with self-signed certificates and for systems to trust
 # the self-signed CA
 - name: Install CA
-  hosts: overcloud
+  hosts: controllers:network
   tasks:
     - name: Copy the intermediate CA
       ansible.builtin.copy:
@@ -16,7 +16,7 @@
       become: true
       ansible.builtin.command: "{{ 'update-ca-trust' if ansible_facts.os_family == 'RedHat' else 'update-ca-certificates' }}"
 - name: Generate backend API certificates
-  hosts: overcloud
+  hosts: controllers:network
   vars:
     vault_api_addr: https://{{ internal_net_name | net_ip(groups['controllers'][0]) }}:8200
     vault_intermediate_ca_name: OS-TLS-INT