Remove now-obsolete shell "warn" parameter

Signed-off-by: Dan Mick <dmick@redhat.com>

Author: ceph-jenkins

deploy/playbooks/roles/common/tasks/rabbitmq.yml

@@ -3,7 +3,6 @@
   become: true
   shell:
     cmd: "curl -1sLf 'https://keys.openpgp.org/vks/v1/by-fingerprint/0A9AF2115F4687BD29803A206B73A36E6026DFCA' | sudo gpg --dearmor | sudo tee /usr/share/keyrings/com.rabbitmq.team.gpg"
-    warn: no
 
 - name: add the Erlang Launchpad PPA key
   become: true