Prepare for dropping keystone admin endpoint

Keystone no longer has any special functionality hidden behind the admin
endpoint. Stop referencing it in consumers, so it can later be dropped
completely.

Change-Id: I04a5d77908005268cc7c59e7e9ddeea70f6732e2
diff --git a/lib/nova_plugins/hypervisor-ironic b/lib/nova_plugins/hypervisor-ironic
index b147c43..bda6ef6 100644
--- a/lib/nova_plugins/hypervisor-ironic
+++ b/lib/nova_plugins/hypervisor-ironic
@@ -46,7 +46,7 @@
     iniset $NOVA_CONF ironic auth_type password
     iniset $NOVA_CONF ironic username admin
     iniset $NOVA_CONF ironic password $ADMIN_PASSWORD
-    iniset $NOVA_CONF ironic auth_url $KEYSTONE_AUTH_URI
+    iniset $NOVA_CONF ironic auth_url $KEYSTONE_SERVICE_URI
     iniset $NOVA_CONF ironic project_domain_id default
     iniset $NOVA_CONF ironic user_domain_id default
     iniset $NOVA_CONF ironic project_name demo