bundles/nginx: clean up unmanaged nginx vhosts

bundles/nginx/items.py

@@ -3,6 +3,15 @@
 # support wildcard certificates
 assert node.has_bundle('letsencrypt'), 'nginx needs letsencrypt'
 
+directories = {
+    '/etc/nginx/sites': {
+        'purge': True,
+        'triggers': {
+            'svc_systemd:nginx:restart',
+        },
+    },
+}
+
 files = {
     '/etc/nginx/nginx.conf': {
         'content_type': 'mako',