Switch Windows Dockerfile to golang 1.5.3
Switch Windows Dockerfile to golang 1.5.3

Also renamed the env-variable to match what
we use in other locations (for easier finding)

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

aditirajagopal/docker,aditirajagopal/docker,aditirajagopal/docker