@pawan - thanks for your prompt response. Let me try that out putting everything in the same RUN statement.
Yes I saw that we checked all the dependencies in the repo, thanks for fixing the build. I just couldn’t resist chasing this govendor bug. 
Welp, I tried your suggestion and it complains saying GOPATH should not be set to GOROOT, which I think is recommended. But not setting GOROOT again brings back the dockerfile execution to an impasse.
I will try to dig into this later.
I also looked into glide’s (glide.sh) behavior with docker - Docker Hub
It doesn’t seem to have any problems. We can always use that as a backup option if we ever decide to move away from checking dependencies into the repo.