build-fast: propagate/include metadata

[cgwalters]

ostree has nice flexible support for injecting metadata into commits. Cool. We've been extensively using it in various ways, e.g coreos-assembler injects basearch and rpm-ostree injects the initramfs-args.

cosa build-fast omits all that stuff. One noticeable side effect of missing the basearch is that zincati goes into a start-die-restart loop (should probably fix cosa to have "this is a fastbuild" flag or something and zincati gracefully shuts down if so?). The only real harm is the spam in the journal, but still.

And a side effect of missing the initramfs-args is that testing rpm-ostree changes in a cosa build-fast and then testing replacing the kernel in there will end up generating a broken initramfs (this took me longer than it should have to figure out, I got distracted by thinking it was selinux because for some reason we're getting a new denial in 33 when rebuilding the initramfs client side).

(I use cosa build-fast a lot)

[cgwalters]

xref coreos/rpm-ostree#2343 for the denial

[jlebon]

This is still relevant I think, though specifically in the initramfs case, I think that was fixed with the recent changes in rpm-ostree to use the treefile instead IIRC.