[luxembourg] servers: Update ntp, fix storage enclosure

data/grid5000/sites/luxembourg/servers/cronos.json

 {
   "alias": [
     "adminfront",
-    "ntp",
     "af",
     "granduc-srv",
     "smokeping"

data/grid5000/sites/luxembourg/servers/md1000.json

+{
+  "alias": [
+
+  ],
+  "kind": "storage",
+  "network_adapters": {
+  },
+  "serial": "6P90J2J",
+  "type": "server",
+  "uid": "md1000",
+  "warranty": 10.2009
+}
\ No newline at end of file

data/grid5000/sites/luxembourg/servers/petitprince-cmc.json

@@ -2,7 +2,7 @@
   "alias": [
     "m1000-cmc"
   ],
-  "kind": "storage",
+  "kind": "physical",
   "network_adapters": {
     "bmc": {
       "ip": "172.17.177.254"

data/grid5000/sites/luxembourg/servers/zeus.json

 {
   "alias": [
     "nfs",
+    "ntp",
     "home-g5k",
     "public"
   ],

input/grid5000/sites/luxembourg/servers/servers.yaml

 cronos:
   kind: physical
-  alias: [adminfront, ntp, af, granduc-srv, smokeping]
+  alias: [adminfront, af, granduc-srv, smokeping]
   warranty: 05.2017
   serial: JSG625J
   network_adapters:
@@ -13,7 +13,7 @@ cronos:
 
 zeus:
   kind: physical
-  alias: [nfs, home-g5k, public]
+  alias: [nfs, ntp, home-g5k, public]
   warranty: 08.2016
   serial: 8L6033J
   network_adapters:
@@ -36,10 +36,17 @@ hera:
       mac: 00:1C:23:D6:C4:E6
 
 petitprince-cmc:
-  kind: storage
+  kind: physical
   alias: [m1000-cmc]
   warranty: 10.2016
   serial: CDQTG5J
   network_adapters:
     bmc:
       ip: 172.17.177.254
+
+md1000:
+  kind: storage
+  alias: []
+  warranty: 10.2009
+  serial: 6P90J2J
+  network_adapters: {}