The repo locations moved in F45+ [1] and so now when
testing F44 in CI we end up with a failure like:
```
[2/3] STEP 2/2: RUN --mount=type=bind,from=repos,src=/,dst=/repos,rw <<EORUN (echo -e '--install\nltrace' > args.txt...)
rpm-ostree version: 2026.2
error: Installing packages: No enabled repositories
error: Executing compose install: ExitStatus(unix_wait_status(256))
Error executing command: Command '['rpm-ostree', 'compose', 'rootfs', '--source-root-rw=/repos', '/tmp/tmpmnq4sg6s.json', '/target-rootfs']' returned non-zero exit status 1.
subprocess exited with status 1
```
Let's drop using the rawhide image just for `repos` and use the
repos baked into the image we built instead (which should match
the target Fedora version we're testing).
[1] https://fedoraproject.org/wiki/Changes/RelocateRpmRepoConfigsToUsr
