dns: move tsig_key into common group variable

The tsig_key value is a shared secret between the hidden-primary and
secondary servers to facilitate secure zone transfers.  Thus we should
store it once in the common "adns" group, rather than duplicating it
in the adns-primary and ads-secondary.

Change-Id: I600f1ecdfc06bda79b6a4ce77253f489ad515fa5

playbooks/zuul/run-base.yaml

@@ -114,8 +114,8 @@
         dest: "/etc/ansible/hosts/{{ item }}"
       loop:
         - group_vars/all.yaml
+        - group_vars/adns.yaml
         - group_vars/adns-primary.yaml
-        - group_vars/adns-secondary.yaml
         - group_vars/bastion.yaml
         - group_vars/eavesdrop.yaml
         - group_vars/nodepool.yaml

playbooks/zuul/templates/group_vars/adns-primary.yaml.j2

@@ -1,6 +1,3 @@
-tsig_key:
-  algorithm: hmac-md5
-  secret: 9zO/4WnUinnLHISPgDI5Aw==
 dnssec_keys:
   '18093':
     zone: zuulci.org