infra-prod: remove duplicated bridge key setup

The known_host key is written out by the parent infra-prod-base job in
the run-production-playbook.yaml step [1].  We don't need to do this
here again.

[1] 2c194e5cbf/playbooks/zuul/run-production-playbook.yaml (L1)

Change-Id: I514132b2dbc20ac321a79ca2eb6d4c8b11c4296d

playbooks/zuul/run-production-playbook.yaml

@@ -1,6 +1,6 @@
 - hosts: localhost
   tasks:
-    - name: Add bridge.o.o to inventory
+    - name: Add bridge.o.o to inventory for playbook
       add_host:
         name: bridge.openstack.org
         ansible_python_interpreter: python3
@@ -11,13 +11,6 @@
         ansible_host: bridge.openstack.org
         ansible_port: 22
 
-- hosts: localhost
-  tasks:
-    - name: Add bridge.o.o hostkey to known hosts
-      known_hosts:
-        name: bridge.openstack.org
-        key: "bridge.openstack.org ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCxRzDkWvvVQtsLTAqAwedRWA84/42KKVdFS0QP8lZFsMpgTXUhjipJ7VcFun5gM87tnt0J71rlN+ospBh0/1wfp2jASEskUyGhXAa5xHjnJN7veUyW+AggEosK/OTunvZgf54p1sQg45Sq/uCjc0Ua0fRMOq2o5z/mgpl6rSjLOlWi9wKA/6axnUbs9w4iD5esyBQ+VcISSJOTqhAo/3UG0NwCU+6Ggwwhg0nl5iCMpQfq4A207IbJ72MkJzlQgW3edsRb5POzdZcGxkTYvVdP3kgHP4Bof3MFFZjBUMz6SuRQyNV5poysMtbtlO0SvgAJNhXr6Vn0GA9XhqFP6+HT"
-
 - hosts: bridge.openstack.org
   tasks:
     - name: Should we run from master