Fix broken Octavia integration in OpenStack External Cloud Provider (#6046)

roles/kubernetes-apps/external_cloud_controller/openstack/templates/external-openstack-cloud-config.j2

@@ -19,7 +19,7 @@ ca-file="{{ kube_config_dir }}/external-openstack-cacert.pem"
 {% endif %}
 
 [LoadBalancer]
-use-octavia={{ external_openstack_lbaas_use_octavia }}
+use-octavia={{ external_openstack_lbaas_use_octavia | string | lower }}
 create-monitor={{ external_openstack_lbaas_create_monitor }}
 monitor-delay={{ external_openstack_lbaas_monitor_delay }}
 monitor-timeout={{ external_openstack_lbaas_monitor_timeout }}
@@ -45,3 +45,6 @@ manage-security-groups={{ external_openstack_lbaas_manage_security_groups }}
 {% if external_openstack_lbaas_internal_lb is defined %}
 internal-lb={{ external_openstack_lbaas_internal_lb }}
 {% endif %}
+{% if external_openstack_lbaas_use_octavia is defined and external_openstack_lbaas_use_octavia %}
+lb-provider=octavia
+{% endif %}