Machine allocation succeeded flag never gets set

[Gerrit91]

Maybe I miss something, but during investigation of #207 I found that the field machine.Allocation.Succeeded field never gets set. I am very confused about this as I thought that this flag toggles in finalize-allocation. It doesn't. And also it seems like in the past it did not.

This is actually dangerous as the metal-core uses this flag do decide whether it lets a machine boot the hammer or not: https://github.com/metal-stack/metal-core/blob/master/internal/endpoint/boot.go#L38

Also the GEPM uses this flag in the firewall reconciliation and it's kind of a miracle that the code just works.