[sirius] Add missing netmask for ib0 interface.

data/grid5000/sites/lyon/clusters/sirius/nodes/sirius-1.json

@@ -198,6 +198,7 @@
       "mountable": true,
       "mounted": true,
       "name": "ib0",
+      "netmask": "255.255.240.0",
       "network_address": "sirius-1-ib0.lyon.grid5000.fr",
       "rate": 10000000000,
       "vendor": "Mellanox Technologies"