The previous value for parent was not a valid commit ID. In a regular
compose request, the parent ref is resolved before being added as a
source in the manifest. However, when building test manifests, since
the values aren't real, we don't resolve the ostree refs, meaning that
the test manifests weren't valid — they failed validity checks if run in
osbuild.
Replaced the fake parent ref with a fake parent commit ID
"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff".
The manifests still aren't buildable, since they don't point to a valid
ostree repository or commit, but now they're at least valid (in the
technical sense).
We used to always set the sysroot.readonly setting to true, but this
never worked because of a bug in osbuild [1].
The bug is now fixed and the RHEL and CentOS edge-raw images are crated
with sysroot.readonly = true, and the images aren't booting.
Fixing the option to false. This changes the manifests, but not the
generated images because of the change in osbuild.
If sysroot is meant to be readonly, we will change it in a future
update.
[1] https://github.com/osbuild/osbuild/pull/1129
