Replace "hash_hostname" with "hash_known_hosts".

The former is deprecated since Carbon.

users/init.sls

@@ -375,8 +375,8 @@ users_ssh_known_hosts_{{ name }}_{{ loop.index0 }}:
     {% if 'enc' in host %}
     - enc: {{ host['enc'] }}
     {% endif -%}
-    {% if 'hash_hostname' in host %}
-    - hash_hostname: {{ host['hash_hostname'] }}
+    {% if 'hash_known_hosts' in host %}
+    - hash_known_hosts: {{ host['hash_known_hosts'] }}
     {% endif -%}
 {% endfor %}
 {% endif %}