Use the good default values for newly indexed error-related fields. Be sure to empty them if everything went fine, to avoid making false-positive errors remain in the database.
bump version in __init__.py
Merge branch 'release/0.20.4.1'
Merge tag '1flow-0.20.4.1' into develop

0.20.4.1
cleanups.
inconditionnaly release the feed refresh lock at the end of the refresh process. The `last_fetch` attribute will do the job against "too near refreshes" protection. No need to flood redis with useless keys.
send absolutize_url() tasks to the `swarm` queue, it's too often blocking the standard queues.
Create the `swarm` queue with eventlet/1000.
Smaller swarm queue on development machines, too.
Bump sparks requirement to 3.7 for celery fine-tuning options.
bump version in __init__.py
Merge branch 'release/0.20.5'
Merge tag '1flow-0.20.5' into develop

0.20.5
development procfile fixes.
add swarm queue to celery settings.
bump version in __init__.py
Merge branch 'hotfix/0.20.5.1'
Merge tag '1flow-0.20.5.1' into develop

0.20.5.1
Switch back to "normal" processes, the swarm worker freezes after 200+ jobs…
No more event let in development, it just doesn't work…