OnConflict::Replace: yield when lock was achieved

[mhenrixon]

Close #629

The replace strategy creates a new lock after deleting the old lock and the old job. After a lock has been achieved we need to allow the worker to yield in that specific scenario.

@dsander can you check if this solves the problem for you?

[dsander]

Thanks for looking into it! Sadly it doesn't work, you can pull in the integration tests I added from this commit projectivetech@23dc652.

When using on_conflict: :replace the middleware can not return nil because that tells sidekiq not to enqueue the new job. An approach similar to :reschedule might work, but then the caller of perform_async still would not get the newly enqueued jid and kind of break the Sidekiq API.

[mhenrixon]

@dsander the tests you provided passes in this branch now

[dsander]

Thank you for fixing it!