Update galera repo url variables during upgrades

Modify the 'Write vars required for upgrade' task to make use of
backrefs so that any user defined variables for galera repo urls
are updated for the expected release of MariaDB.

Change-Id: I56aad0dd48df4f8e80d1b33a4130daa575b1814b

scripts/upgrade-utilities/playbooks/deploy-config-changes.yml

@@ -66,9 +66,25 @@
       - name: Write vars required for upgrade
         lineinfile:
           dest: /etc/openstack_deploy/user_variables.yml
-          regexp: "^{{ item.key }}"
+          regexp: "{{ item.regexp | default('^' + item.key) }}"
           line: "{{ item.key }}: {{ item.value }}"
+          backrefs: "{{ item.backrefs | default('no') }}"
           state: present
         with_items:
           - key: "default_bind_mount_logs"
-            value: false
+            value: "false"
+          # Replace "10.0" with "10.1" within galera_repo_url
+          - key: "galera_repo_url"
+            regexp: '^galera_repo_url: (https?://.*10)\.0(.*)$'
+            value: '\1.1\2'
+            backrefs: yes
+          # Replace "10.0" with "10.1" within galera_client_apt_repo_url
+          - key: "galera_client_apt_repo_url"
+            regexp: '^galera_client_apt_repo_url: (https?://.*10)\.0(.*)$'
+            value: '\1.1\2'
+            backrefs: yes
+          # Replace "10.0" with "10.1" within galera_client_repo_url
+          - key: "galera_client_repo_url"
+            regexp: '^galera_client_repo_url: (https?://.*10)\.0(.*)$'
+            value: '\1.1\2'
+            backrefs: yes