pipeline: show: outs: improper DAG

See https://discordapp.com/channels/485586884165107732/485586884165107734/557205322641702912 . We should connect outputs to dependencies here https://github.com/iterative/dvc/blob/0.32.1/dvc/command/pipeline.py#L70 instead of connecting all outputs to all outputs of a dependant stage.