Make "Check if firewalld is installed" task quieter

Stop showing the task has having made changes and silence warning about
not using the yum module (which we could use for the check, but not as
easily).

Change-Id: I9e3608b5db521930409a29981767f468ea234679

ansible/roles/baremetal/tasks/install.yml

@@ -17,7 +17,10 @@
 - name: Check if firewalld is installed
   command: rpm -q firewalld
   register: firewalld_check
+  changed_when: false
   failed_when: firewalld_check.rc > 1
+  args:
+    warn: false
   when: ansible_os_family == 'RedHat'
 
 - name: Disable firewalld