purge-cluster: Do not use shell for rm

The shell wildcard expansion of non-existing paths fails on zsh making
the whole script fail. We can use file module with with_fileglob to
alleviate the problem instead.

Signed-off-by: Boris Ranto <branto@redhat.com>

infrastructure-playbooks/purge-cluster.yml

@@ -692,7 +692,10 @@
     failed_when: check_for_running_ceph.rc == 0
 
   - name: remove ceph systemd unit files
-    shell: rm -rf /etc/systemd/system/ceph*
+    file:
+      path: "{{ item }}"
+      state: absent
+    with_fileglob: /etc/systemd/system/ceph*
     changed_when: false
     when: ansible_service_mgr == 'systemd'