users.yml: add task to ensure root's .ssh directory exists.

roles/common/tasks/users.yml

@@ -153,6 +153,11 @@
 # - Allow connection via ssh to backup host
 # ---
 
+- name: Ensure root's .ssh directory exists
+  file:
+    path: /root/.ssh
+    state: directory
+
 - name: (users.yml) Copy default ed25519 ssh private key to user root
   copy:
     src: '{{ item.priv_key_src }}'