dd status=none does not exist on macOS

Redirect transfer stats to /dev/null instead

cluster/gce/config-default.sh

@@ -214,7 +214,7 @@ resources:
     - aesgcm:
         keys:
         - name: key1
-          secret: $(dd if=/dev/random bs=32 count=1 status=none | base64 | tr -d '\r\n')
+          secret: $(dd if=/dev/random bs=32 count=1 2>/dev/null | base64 | tr -d '\r\n')
 EOM
 )
 fi