On task setup script failure, tasks should be marked as "failed" and nodes should be re-imaged

[bmc-msft]

Information

• Onefuzz version: 1.0.0
• OS: Ubuntu 18.04

Provide detailed reproduction steps (if any)

1. Launch a task with a custom setup script (setup.sh) with a failure (say, 'exit 1')

Expected result

1. Task state set to failed. Stderr/stdout from the setup script should be added to task.error
2. Node is appropriately reimaged (/onefuzz/<task_id> no longer exists)

Actual result

1. Task state is scheduled
2. Verify /onefuzz/<task_id> on the node the task was assigned