[octavia] Adds region_name if enable_barbican

Adds necessary "region_name" to octavia.conf when
"enable_barbican" is set to "true".

Closes-Bug: #1867926

Change-Id: Ida61cef4b9c9622a5e925bac4583fba281469a39

ansible/roles/octavia/templates/octavia.conf.j2

@@ -13,6 +13,9 @@ bind_port = {{ octavia_api_listen_port }}
 ca_private_key_passphrase = {{ octavia_ca_password }}
 ca_private_key = /etc/octavia/certs/private/cakey.pem
 ca_certificate = /etc/octavia/certs/ca_01.pem
+{% if enable_barbican | bool %}
+region_name = {{ openstack_region_name }}
+{% endif %}
 
 [haproxy_amphora]
 server_ca = /etc/octavia/certs/ca_01.pem

releasenotes/notes/add-region-name-for-octavia-292594e29ef36bf2.yaml

+---
+fixes:
+  - |
+    Adds necessary ``region_name`` to ``octavia.conf`` when
+    ``enable_barbican`` is set to ``true``. `LP#1867926
+    <https://launchpad.net/bugs/1867926>`__