Yoga: update Kolla build source branches

Author: markgoddard

etc/kayobe/kolla.yml

@@ -118,11 +118,11 @@ kolla_sources:
   cloudkitty-base:
     type: git
     location: https://github.com/stackhpc/cloudkitty.git
-    reference: stackhpc/xena
+    reference: stackhpc/{{ openstack_release }}
   horizon-plugin-cloudkitty-dashboard:
     type: git
     location: https://github.com/stackhpc/cloudkitty-dashboard.git
-    reference: stackhpc/xena
+    reference: stackhpc/{{ openstack_release }}
   ironic-inspector-additions-stackhpc-inspector-plugins:
     # Install our custom inspector plugins.
     type: git
@@ -131,11 +131,11 @@ kolla_sources:
   magnum-base:
     type: git
     location: https://github.com/stackhpc/magnum.git
-    reference: stackhpc/xena
+    reference: stackhpc/{{ openstack_release }}
   neutron-base-plugin-networking-generic-switch:
     type: git
     location: https://github.com/stackhpc/networking-generic-switch.git
-    reference: stackhpc/xena
+    reference: stackhpc/{{ openstack_release }}
 
 ###############################################################################
 # Kolla image build configuration.