Remove a channel close that can panic
Remove a channel close that can panic

This channel close can panic if a different goroutine calls Shutdown at
the same time. The close is redundant anyway - the caller of Run will
call Shutdown on an error. Remove it.

Signed-off-by: Aaron Lehmann <8ecfc6017a87905413dcd7d63696a2a4c351b604@docker.com>

aaronlehmann/swarmkit,Noyan759/swarmkit,AliyunContainerService/swarmkit,cheyang/swarmkit,docker/swarmkit,docker/swarmkit,alyyousuf7/swarmkit,yongtang/swarmkit,vasil-yordanov/swarmkit,aaronlehmann/swarmkit,RenaudWasTaken/swarmkit,sungwonh/swarmkit,sungwonh/swarmkit,elifa/swarmkit,cheyang/swarmkit,runshenzhu/swarmkit,deljuven/swarmkit,jlhawn/swarmkit,elifa/swarmkit,Noyan759/swarmkit,AliyunContainerService/swarmkit,yp-engineering/swarmkit,runshenzhu/swarmkit,alyyousuf7/swarmkit,allencloud/swarmkit,fate-grand-order/swarmkit,diogomonica/swarmkit,deljuven/swarmkit,fate-grand-order/swarmkit,RenaudWasTaken/swarmkit,allencloud/swarmkit,dperny/swarmkit-1,dperny/swarmkit-1,cezarsa/swarmkit,diogomonica/swarmkit,yp-engineering/swarmkit,cezarsa/swarmkit,jlhawn/swarmkit,yongtang/swarmkit,vasil-yordanov/swarmkit