Fix service_type of Octavia

Currently service_type value of Octavia is 'application-catalog', which is obviously wrong.
It must be 'load-balancer'.

See https://developer.openstack.org/api-ref/load-balancer/v2/index.html

Change-Id: Ic457e6d06adb9541273dd3bf191d60cb4421e1c9
Closes-Bug: #1697337

ansible/roles/octavia/tasks/register.yml

@@ -4,8 +4,8 @@
     module_name: "kolla_keystone_service"
     module_args:
       service_name: "octavia"
-      service_type: "application-catalog"
-      description: "Openstack Application Catalogue"
+      service_type: "load-balancer"
+      description: "Octavia Load Balancing Service"
       endpoint_region: "{{ openstack_region_name }}"
       url: "{{ item.url }}"
       interface: "{{ item.interface }}"