copy certificates as root user

Since the current user on the controller node, might not have the
permission to read the TLS certificate and related files, copy these
files to the Ceph nodes as root user.

Fixes: https://github.com/ceph/ceph-ansible/issues/3465
Signed-off-by: Rishabh Dave <ridave@redhat.com>

roles/ceph-iscsi-gw/tasks/deploy_ssl_keys.yml

@@ -57,5 +57,6 @@
     owner: root
     group: root
     mode: 0400
+  become: true
   changed_when: false
   with_items: "{{ crt_files }}"