Enforce server_name in return header

piku.py

@@ -139,7 +139,7 @@ NGINX_PORTMAP_FRAGMENT = """
     proxy_http_version 1.1;
     proxy_set_header Upgrade $http_upgrade;
     proxy_set_header Connection "upgrade";
-    proxy_set_header Host $http_host;
+    proxy_set_header Host $host;
     proxy_set_header X-Forwarded-Proto $scheme;
     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     proxy_set_header X-Remote-Address $remote_addr;