[louvain] fix-missing DNS aliases

data/grid5000/sites/louvain/servers/kavlan.json

 {
+  "alias": [
+    "kavlan-dhcp"
+  ],
   "kind": "virtual",
   "network_adapters": {
     "default": {

data/grid5000/sites/louvain/servers/oar.json

 {
+  "alias": [
+    "oar-server",
+    "oardb"
+  ],
   "kind": "virtual",
   "network_adapters": {
     "default": {

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

@@ -77,12 +77,17 @@ api-proxy:
 
 oar:
   kind: virtual
+  alias:
+  - oar-server
+  - oardb
   network_adapters:
     default:
       ip: 172.16.223.116
 
 kavlan:
   kind: virtual
+  alias:
+  - kavlan-dhcp
   network_adapters:
     default:
       ip: 172.16.223.117