Run a noop on all zookeeper servers first

We need to touch them so that all of their hostvars are visible
in playbooks/roles/zookeeper/templates/zoo.cfg.j2

Change-Id: I04f225269ac31a4890f692c214e8ffb8878833aa

playbooks/service-zookeeper.yaml

@@ -1,3 +1,13 @@
+# We exclude !disabled because we want to run the noop task on all
+# of the hosts in the group, not just the active ones, because we're
+# pulling their hostvars from the fact cache. They don't stop being
+# zookeeper servers just because they are disabled.
+- hosts: "zookeeper"
+  tasks:
+    - name: Use the host so we have access to its hostvars
+      debug:
+        msg: "This debug statement is to get us access to hostvars"
+
 - hosts: "zookeeper:!disabled"
   name: "Configure Zookeeper"
   serial: 1