Fix typo in nginx.server.proxy.openstack_api

Introduced by e95cfa44b.
diff --git a/nginx/server/proxy/openstack_api.yml b/nginx/server/proxy/openstack_api.yml
index 441477f..a3182e5 100644
--- a/nginx/server/proxy/openstack_api.yml
+++ b/nginx/server/proxy/openstack_api.yml
@@ -24,7 +24,7 @@
           type: nginx_proxy
           name: openstack_api_keystone_private
           proxy:
-            host: ${_param:keystone_service_hsot}
+            host: ${_param:keystone_service_host}
             port: 35357
             protocol: http
             filter: