fix variable name

tasks/users_keys.yml

@@ -5,7 +5,7 @@
         user: "{{ item.name }}"
         key: "{{ item.key }}"
         state: present
-      loop: "{{ users_users }}"
+      loop: "{{ users_default_users }}"
       loop_control:
         label: "{{ item.name }}"
       when: item.key is defined