Downgrade celery and dependend libraries (billiard, kombu).
Downgrade celery and dependend libraries (billiard, kombu).

This might be related to an exception we started to see on production:

File "/usr/lib64/python2.7/site-packages/billiard/pool.py", line 1626, in _terminate_pool :/usr/lib/python2.7/site-packages/celery/utils/log.py:282
...

(no full traceback available unfortunately)

Also, I noticed that I didn't see the requirement of celery for billiard> 3.3, <3.4 so let's downgrade for now and be more careful next time.

harikishen/addons-server,Revanth47/addons-server,mozilla/olympia,eviljeff/olympia,mozilla/olympia,mozilla/addons-server,aviarypl/mozilla-l10n-addons-server,diox/olympia,mstriemer/olympia,kumar303/addons-server,kumar303/addons-server,diox/olympia,tsl143/addons-server,kumar303/olympia,wagnerand/addons-server,Revanth47/addons-server,atiqueahmedziad/addons-server,psiinon/addons-server,psiinon/addons-server,mozilla/addons-server,mstriemer/addons-server,mstriemer/addons-server,mstriemer/olympia,atiqueahmedziad/addons-server,mstriemer/olympia,kumar303/olympia,tsl143/addons-server,eviljeff/olympia,bqbn/addons-server,Revanth47/addons-server,kumar303/addons-server,diox/olympia,wagnerand/olympia,lavish205/olympia,wagnerand/olympia,kumar303/addons-server,diox/olympia,mozilla/addons-server,wagnerand/olympia,wagnerand/olympia,bqbn/addons-server,wagnerand/addons-server,harikishen/addons-server,harry-7/addons-server,tsl143/addons-server,mstriemer/addons-server,mozilla/addons-server,aviarypl/mozilla-l10n-addons-server,aviarypl/mozilla-l10n-addons-server,harry-7/addons-server,harry-7/addons-server,kumar303/olympia,mozilla/olympia,wagnerand/addons-server,atiqueahmedziad/addons-server,psiinon/addons-server,harry-7/addons-server,aviarypl/mozilla-l10n-addons-server,bqbn/addons-server,wagnerand/addons-server,eviljeff/olympia,harikishen/addons-server,atiqueahmedziad/addons-server,lavish205/olympia,Revanth47/addons-server,lavish205/olympia,eviljeff/olympia,psiinon/addons-server,harikishen/addons-server,mozilla/olympia,mstriemer/addons-server,mstriemer/olympia,kumar303/olympia,lavish205/olympia,tsl143/addons-server,bqbn/addons-server