Adding "-F /dev/null" to load null SSH config file. (#4933)

roles/bastion-ssh-config/templates/ssh-bastion.conf

@@ -15,4 +15,4 @@ Host {{ bastion_ip }}
   ControlPersist 5m
 
 Host {{ vars['hosts'] }}
-  ProxyCommand ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -W %h:%p {{ real_user }}@{{ bastion_ip }} {% if ansible_ssh_private_key_file is defined %}-i {{ ansible_ssh_private_key_file }}{% endif %}
+  ProxyCommand ssh -F /dev/null -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -W %h:%p {{ real_user }}@{{ bastion_ip }} {% if ansible_ssh_private_key_file is defined %}-i {{ ansible_ssh_private_key_file }}{% endif %}