[nancy] add srv4 hypervisor

data/grid5000/sites/nancy/servers/srv4.json

+{
+  "kind": "physical",
+  "network_adapters": {
+    "adm": {
+      "ip": "172.17.79.37"
+    },
+    "bmc": {
+      "ip": "172.17.79.38",
+      "mac": "5E:ED:8C:39:37:F0"
+    },
+    "default": {
+      "ip": "172.16.79.37",
+      "mac": "30:3E:A7:00:C8:28"
+    }
+  },
+  "pdu": [
+    {
+      "port": 6,
+      "uid": "gruss-pdu1"
+    },
+    {
+      "port": 6,
+      "uid": "gruss-pdu2"
+    }
+  ],
+  "serial": "CZJ24220C6",
+  "type": "server",
+  "uid": "srv4"
+}
\ No newline at end of file