Place sshd-config changes at the begining of the file

So my test case for the last commit was one match statement,
rhos-11 uses two, Ansible interprets "insert before" as
inserting before the *second* match....

ansible/ansible#20582

Change-Id: I450f4c880bcabfc2a6025130608f5dc6c38eb43f

ansible/install/roles/no-sshd-dns/tasks/main.yml

@@ -6,7 +6,7 @@
       dest: /etc/ssh/sshd_config
       line: "UseDNS no"
       state: present
-      insertbefore: '^Match'
+      insertbefore: BOF
   when: "{{disable_ssh_dns}}"
   become: true
   become_user: root