Fix Unrecognized job_state '?' warning

[chrisjsewell]

Just a minor annoyance, but when I use engine.run in an interactive terminal, if the process takes more than a few minutes, I start getting a lot of warnings printed:

07/01/2019 05:56:01 PM <26394> aiida.scheduler.direct: [WARNING] Unrecognized job_state '?' for job id 8399

[sphuber]

This is with the direct scheduler on a localhost computer?

[chrisjsewell]

This is with the direct scheduler on a localhost computer?

Yep. There doesn't seem to be any issue with the runs actually completing.

[ltalirz]

Confirmed; e.g. using the script from #4298 (comment)
(to set up the code, do verdi code setup --config .github/config/add.yaml).

It does not need to be in an interactive terminal, I've also seen it happen simply with verdi run script.py
I may have misunderstood what Chris meant by "interactive terminal" - in any case, it happens when you use engine.run.