kitchen needs to distinguish 3 types of recipe run results: success, failure, infra failure. For infra failures, kitchen needs to distinguish failures in recipe engine (kernel space) from other infra failures (user space), so we can alert on recipe engine bugs.

Per offline discussion with iannucci@, recipe engine's result.proto needs to refactored to represent these 3 types of results, and the infra failure type should include type of infra failure: 
1) exception in recipe engine
2) failure of infra step
3) RunSteps raised unexpected exception