Misc release script improvements
Misc release script improvements

Signed-off-by: Joffrey F <2e95f49799afcec0080c0aeb8813776d949e0768@docker.com>

vdemeester/docker-py,docker/docker-py,docker/docker-py,youhong316/docker-py,youhong316/docker-py,vdemeester/docker-py,funkyfuture/docker-py,funkyfuture/docker-py