Remove Celery task_acks_late (#1469)

This is to disable implicit retries by Celery because it causes duplicate tasks that the task manager does not deal with appropriately when a task has timed out because the task stub has already been removed, which means that new Jobs do not get created based on the output evidence from the retried task.

turbinia/tcelery.py

@@ -56,7 +56,6 @@ def setup(self):
         broker_connection_retry_on_startup=True,
         task_default_queue=config.INSTANCE_ID,
         accept_content=['json'],
-        task_acks_late=True,
         worker_cancel_long_running_tasks_on_connection_loss=True,
         worker_concurrency=1,
         worker_prefetch_multiplier=1,