[lille] add kind key on git-archive

data/grid5000/sites/lille/servers/git-archive.json

 {
+  "kind": "virtual",
   "network_adapters": {
     "default": {
       "ip": "172.16.47.114"

input/grid5000/sites/lille/servers/virtual.yaml

@@ -276,6 +276,7 @@ oargrid-dev:
     default:
       ip: 172.16.47.113
 git-archive:
+  kind: virtual
   network_adapters:
     default:
       ip: 172.16.47.114