Point opencontainers/specs to proper upstream
Point opencontainers/specs to proper upstream

Signed-off-by: Gareth Smith <97ec7f0e37ed298c6c7d61e7dba0820f215e55e4@pivotal.io>

cloudfoundry-incubator/guardian-release,cloudfoundry-incubator/guardian-release,cloudfoundry-incubator/guardian-release