This adds syncing for multi-arch ostrees. Tested this out
in stage by commenting out various parts of the script and
running it. See following logs:
INFO:updates-sync:OSTree at /mnt/fedora_koji_prod/koji/atomic/27, ref
fedora/27/x86_64/testing/atomic-host in sync
INFO:updates-sync:Syncing OSTree to /mnt/fedora_koji_prod/koji/atomic/27, ref
fedora/27/aarch64/testing/atomic-host:
29757b6c48f12cf9121eca6ff5ec297a328541d4a24f6b688d9ca2b866de463c -> ----
INFO:updates-sync:Syncing OSTree to /mnt/fedora_koji_prod/koji/atomic/27, ref
fedora/27/ppc64le/testing/atomic-host:
8bf273ceb73582e8c9432229529d6f9a24442b26deab5db2d4b7cffa4896558a -> ----
INFO:updates-sync:OSTree at /mnt/fedora_koji_prod/koji/atomic/27, ref
fedora/27/x86_64/updates/atomic-host in sync
INFO:updates-sync:Syncing OSTree to /mnt/fedora_koji_prod/koji/atomic/27, ref
fedora/27/aarch64/updates/atomic-host:
2111ab79828346c0d34ee7e60a80baef68e6b137ce54ccb0e82e5ffad354b099 ->
a4459cbd87b23749bc49ca5875b6bc3b03a9edcaaebbcb4bc55dabba7f4611d9
INFO:updates-sync:Syncing OSTree to /mnt/fedora_koji_prod/koji/atomic/27, ref
fedora/27/ppc64le/updates/atomic-host:
90806822b053d30a07e833ac5bd2c7c5979e1c7f53d1d0cd62c093eb7c8207f7 ->
33e605a413818d3de5f88eddf9e5aa4450591a40a026d0f6ee462e67445918c4
INFO:updates-sync:OSTree at /mnt/fedora_koji_prod/koji/atomic/26, ref
fedora/26/x86_64/testing/atomic-host in sync
INFO:updates-sync:OSTree at /mnt/fedora_koji_prod/koji/atomic/26, ref
fedora/26/x86_64/updates/atomic-host in sync