try to fix another code block

howto/ganeti.md

@@ -646,7 +646,7 @@ Import procedure:
 
  12. retire old instance (only a tiny part of [howto/retire-a-host](howto/retire-a-host)):
  
-        ./retire -H $INSTANCE retire-instance --parent-host $KVM_HOST
+         ./retire -H $INSTANCE retire-instance --parent-host $KVM_HOST
 
  12. update the [Nextcloud spreadsheet](https://nc.torproject.net/apps/onlyoffice/5395) to remove the machine from
      the KVM host