Change the order of horizon-back map entry

Horizon's '.*' regex should be used as fallback if all other
map entries do not match, so its order shouldn't have default default(00)
order. This patch changes it to 99.

Change-Id: I36a60b5fabcb8306f98298f3d8961bacf708228a

inventory/group_vars/haproxy/haproxy.yml

@@ -271,6 +271,7 @@ haproxy_horizon_service:
   haproxy_stick_table: "{{ openstack_haproxy_horizon_stick_table }}"
   haproxy_map_entries:
     - name: base_regex
+      order: 99
       #match any requests to the horizon backend
       entries:
         - '.* horizon-back'