Remove hostname validation
Remove hostname validation

Signed-off-by: Vincent Demeester <87e1f221a672a14a323e57bb65eaea19d3ed3804@sbr.pm>

aaronlehmann/swarmkit,dperny/swarmkit-1,diogomonica/swarmkit,docker/swarmkit,cheyang/swarmkit,alyyousuf7/swarmkit,fate-grand-order/swarmkit,AliyunContainerService/swarmkit,Noyan759/swarmkit,cheyang/swarmkit,elifa/swarmkit,allencloud/swarmkit,RenaudWasTaken/swarmkit,sungwonh/swarmkit,yongtang/swarmkit,AliyunContainerService/swarmkit,fate-grand-order/swarmkit,dperny/swarmkit-1,deljuven/swarmkit,elifa/swarmkit,alyyousuf7/swarmkit,jlhawn/swarmkit,aaronlehmann/swarmkit,sungwonh/swarmkit,jlhawn/swarmkit,diogomonica/swarmkit,docker/swarmkit,deljuven/swarmkit,RenaudWasTaken/swarmkit,Noyan759/swarmkit,yongtang/swarmkit,allencloud/swarmkit