[nancy][grdix] change bmc mac adr for grdix-11

data/grid5000/sites/nancy/clusters/grdix/nodes/grdix-11.json

@@ -222,7 +222,7 @@
       "interface": "Ethernet",
       "ip": "172.17.65.21",
       "kavlan": false,
-      "mac": "5c:ed:8c:01:8d:7c",
+      "mac": "7c:a6:2a:4e:e1:06",
       "management": true,
       "mountable": false,
       "mounted": false,