[drac] Add standard environment variable

input/grid5000/sites/grenoble/clusters/drac/drac.yaml

@@ -19,6 +19,8 @@ nodes:
       deploy: true
       besteffort: true
       max_walltime: 0
+    software:
+      standard-environment: debian10-ppc64-std
     network_adapters:
       bmc:
         interface: Ethernet