Renames auth.token.rootCertBundle field in registry config to rootcertbundle so that the REGISTRY_AUTH_TOKEN_ROOTCERTBUNDLE environment variable will override it. See ()[https://github.com/docker/distribution/blob/master/configuration/parser.go#L155] Signed-off-by: Donald Huang <don.hcd@gmail.com>
Signed-off-by: Stephen J Day <stephen.day@docker.com>