changes included: - swarmkit #2706 address unassigned task leak when service is removed - swarmkit #2676 Fix racy batching on the dispatcher - swarmkit #2693 Fix linting issues revealed by Go 1.11 Signed-off-by: Sebastiaan van Stijn <github@gone.nl> Upstream-commit: c9377f45529d5dce21c264947b73c7053f316467 Component: engine