failure during StateIO export not obvious

[ghukill]

Error with host handling for ElasticSearch -- related to Docker deploy -- but this error backed out of later processes. Export appeared to work, but was virtually empty. Need to detect error and report somehow, perhaps in export_manifest.json?

[antmoth]

Relevant to the "export everything, nuke, and reinstall" update process.

[antmoth]

Problems also crop up on import, both with displaying failure on the background tasks page and with the StateIO page not showing that the job has even completed, much less failed.

Easy to reproduce on import: try to import a job created by a user of an id that doesn't exist in your system