* docker-pull timeout is now a 504 which classifies it as a
service error. Avoid using 503 to make sure LB does not retry.
* Only applicable to detached mode, a timeout on LB is
now a ErrServiceReservationFailure (500). In detached mode,
this is unlikely to make it back to a client and it is mostly
for documentation/metrics purposes.
* For Triggers, avoid scrubbing service code.