eval_failed event: change interface to traceID\tjobsetID

I was not going to break the interface until I noticed the other eval_* events used literal \ts

src/lib/Hydra/Event.pm

@@ -8,6 +8,7 @@ use Hydra::Event::BuildStarted;
 use Hydra::Event::CachedBuildFinished;
 use Hydra::Event::CachedBuildQueued;
 use Hydra::Event::EvalCached;
+use Hydra::Event::EvalFailed;
 use Hydra::Event::EvalStarted;
 use Hydra::Event::StepFinished;
 
@@ -18,6 +19,7 @@ my %channels_to_events = (
   cached_build_finished => \&Hydra::Event::CachedBuildFinished::parse,
   cached_build_queued => \&Hydra::Event::CachedBuildQueued::parse,
   eval_cached => \&Hydra::Event::EvalCached::parse,
+  eval_failed => \&Hydra::Event::EvalFailed::parse,
   eval_started => \&Hydra::Event::EvalStarted::parse,
   step_finished => \&Hydra::Event::StepFinished::parse,
 );