Fix rabbitmq 'pungi' user creation on prod

I think @kevin inadvertently broke this in
f0663ae52f - he mixed up the names
of environments ('production' / 'staging') and Koji instances
('primary' / 'secondary'), just in this one case (it's correct
everywhere else). This is causing the pungi user not to be
created, and that means compose hosts can't publish messages.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

playbooks/groups/releng-compose.yml

@@ -159,7 +159,7 @@
   - role: rabbit/user
     user_name: "pungi{{ env_suffix }}"
     user_sent_topics: ^org\.fedoraproject\.{{ env_short }}\.(pungi|compose|logger)\..*
-    when: koji_instance == "production" or env == "staging"
+    when: koji_instance == "primary" or env == "staging"
 
   - {
     role: "push-container-registry",