Add yaml vars to focal-ussuri bundle

This brings it into line with the other charms that are part of the the
enable-focal topic.  This makes it easier to add a new bundle just by
changing a couple of variables.

Change-Id: If45c350bb782b5e3367e97153379f2706f8fe4c9

tests/bundles/focal-ussuri.yaml

@@ -1,4 +1,8 @@
+variables:
+  openstack-origin: &openstack-origin distro
+
 series: focal
+
 comment:
 - 'machines section to decide order of deployment. database sooner = faster'
 machines:
@@ -12,41 +16,53 @@ machines:
   '4':
   '5':
   '6':
-relations:
-- - keystone:shared-db
-  - keystone-mysql-router:shared-db
-- - glance:shared-db
-  - glance-mysql-router:shared-db
-- - glance:identity-service
-  - keystone:identity-service
-- - glance-mysql-router:db-router
-  - mysql-innodb-cluster:db-router
-- - keystone-mysql-router:db-router
-  - mysql-innodb-cluster:db-router
+
 applications:
+
   glance-mysql-router:
     charm: cs:~openstack-charmers-next/mysql-router
   keystone-mysql-router:
     charm: cs:~openstack-charmers-next/mysql-router
+
   mysql-innodb-cluster:
     charm: cs:~openstack-charmers-next/mysql-innodb-cluster
     num_units: 3
+    options:
+      source: *openstack-origin
     to:
       - '0'
       - '1'
       - '2'
+
   keystone:
     charm: ../../../keystone
     num_units: 3
     options:
+      openstack-origin: *openstack-origin
       token-provider: 'fernet'
       token-expiration: 60
     to:
     - '3'
     - '4'
     - '5'
+
   glance:
     charm: cs:~openstack-charmers-next/glance
     num_units: 1
+    options:
+      openstack-origin: *openstack-origin
     to:
     - '6'
+
+relations:
+
+  - - 'keystone:shared-db'
+    - 'keystone-mysql-router:shared-db'
+  - - 'glance:shared-db'
+    - 'glance-mysql-router:shared-db'
+  - - 'glance:identity-service'
+    - 'keystone:identity-service'
+  - - 'glance-mysql-router:db-router'
+    - 'mysql-innodb-cluster:db-router'
+  - - 'keystone-mysql-router:db-router'
+    - 'mysql-innodb-cluster:db-router'