Bump Go to 1.9.3
Bump Go to 1.9.3

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

dperny/swarmkit-1,docker/swarmkit,alyyousuf7/swarmkit,dperny/swarmkit-1,docker/swarmkit,alyyousuf7/swarmkit