Fix typo SCS-2D -> SCS-2C as flavor default for controller.

Created by: garloff

Note: This gives us SCS-2C:4:20s, which is a flavor with 2 dedicated cores and a (local) 20GB SSD disk. This would be a good choice for control plane nodes and what was intended before. We have plans to standardize a SCS-2V:4:20s flavor, so this will eventually become the default here. We have not observed issues with excessive steal time for etcd, so this is believed to be good enough.

Signed-off-by: Kurt Garloff kurt@garloff.de