[JENKINS-22960] wait for build to be finalized (part 1/2)

When a build is complete, not everything is written to disk.
This is a problem when you try to consume artifacts
(e.g. `slurpArtifacts()` in https://github.com/dnozay/build-flow-toolbox-plugin)
Wait for build to be finalized instead.
[JENKINS-22960] wait for build to be finalized (part 2/2)

actually enable the waiting for finalization.
Merge pull request #44 from dnozay/finalize

[FIXED JENKINS-22960]. wait for build to be finalized