Mark finished release and don't consider un-finished releases in rollback

[pableu]

A better solution, as figured out in #4114.

We want to track successfully finished releases, and only roll back to these in dep rollback.

Otherwise, we might roll back to a semi-released deployment, e.g., one we aborted with CTRL+C or where something else went wrong.

[antonmedv]

Please fix:

[pableu]

Alrighty, done @antonmedv.