boot2docker shellinit will set any and all env vars needed.

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
Merge pull request #8116 from SvenDowideit/use-boot2docker-shellinit

boot2docker shellinit will set any and all env vars needed.