distro/fedora: print an error if PackageSets cannot initialize a manifest

Previously, this just happened silently and let to extremely odd errors. Let's
just print the error to simplify debugging the next time.

Signed-off-by: Ondřej Budai <ondrej@budai.cz>

internal/distro/fedora/distro.go

@@ -561,6 +561,7 @@ func (t *imageType) PackageSets(bp blueprint.Blueprint, options distro.ImageOpti
 	if err != nil {
 		// TODO: handle manifest initialization errors more gracefully, we
 		// refuse to initialize manifests with invalid config.
+		logrus.Errorf("Initializing the manifest failed for %s (%s/%s): %v", t.Name(), t.arch.distro.Name(), t.arch.Name(), err)
 		return nil
 	}