roles/ssh_server: fix error on waiting for...

Fix an error when `ssh_server` last task, the one that checks if the
server has actually started to listen on port 22.

This error occurred while using the `ssh_server` role on a physical
host, not while running on lxc_guests.

roles/ssh_server/tasks/main.yaml

@@ -118,5 +118,5 @@
     host: '{{ hostvars | ip_from_inventory(inventory_hostname) }}'
     port: 22
     timeout: 30
-  delegate_to: '{{ inventory_hostname }}'
+  delegate_to: 'localhost'
   delegate_facts: true