if a recipe engine, not the user recipe, fails, kitchen must mark the build as an internal failure. We must get notified when this happens.

proposal:
- implement as a counter metric for a builds with fields "status" ("success", "failure"), "failed component" ("", "kitchen", "recipe_engine", "recipe", "logdog"?). 
- implement on alert on positive number of non-recipe failures

Re counter: there are many instances of kitchen, so either have to
- introduce new field "bot_id". Won't work if we have builds too often.
- introduce new field "swarming_run_id" and use autogen to collapse swarming_run_id fields in a precomtutation