rkt fetch broken on arm64

[Geoff Levand]

ProblemType: Bug
ApportVersion: 2.20.4-0ubuntu4.5
Architecture: arm64
Date: Tue Aug 29 15:03:36 2017
Package: rkt 1.21.0+dfsg-1
PackageArchitecture: arm64
ProcVersionSignature: Ubuntu 4.10.0-32.36-generic 4.10.17
SourcePackage: rkt
Tags: zesty
Uname: Linux 4.10.0-32-generic aarch64
UpgradeStatus: No upgrade log present (probably fresh install)
_MarkForUpload: True

The rkt version packaged in zesty has a known bug that does not allow it to use docker images on arm64 systems.

The upstream fix: https://github.com/rkt/rkt/pull/3534
Fixed in rkt release: rkt-1.23.0

To reproduce:

$ sudo rkt --debug --insecure-options=image fetch docker://aarch64/ubuntu:latest

fetch:
  └─error converting docker image to ACI
    └─error generating ACI: bad arch "arm64" for linux (must be one of: [amd64 i386 aarch64 aarch64_be armv6l armv7l armv7b ppc64 ppc64le s390x])