fix version marshalling

docker/docker.go

@@ -244,7 +244,6 @@ func StartContainer(containerName string, containerType string) (structs.Contain
 func GetLatestContainerInfo(containerType string) (map[string]string, error) {
 	var res map[string]string
 	conf := config.Conf()
-	releaseChannel := conf.UpdateBranch
 	arch := config.Architecture
 	hashLabel := arch + "_sha256"
 	versionInfo := config.VersionInfo