[esterel6] Fix bmc version

data/grid5000/sites/sophia/clusters/esterel6/nodes/esterel6-1.json

@@ -11,7 +11,7 @@
     "vendor": "Dell Inc.",
     "version": "2.18.2"
   },
-  "bmc_version": "unknown",
+  "bmc_version": "2.85.85.85",
   "chassis": {
     "manufactured_at": "2017-04-18",
     "manufacturer": "Dell Inc.",