This:
- reworks how retries are handled in fi/executor.go to a time-based scheme
- changes the single-task limit to 10m (from about 30s of no-progress)
- eliminates the inner IAM propagation retry for LaunchConfigurations,
because the task itself will just be redriven for a while. This also
eliminates any long-pole delay caused by this error (since task Run()
should be 'fast').
Beginnings of a mock for the AWSCloud, so that hopefully we aren't
calling out to AWS at all in the tests. We will likely start mocking
the actual EC2 APIs in future, but this seems a good starting point.
Fix#425