Run various cleanup operations without the base trees mounted

When running cleanup operations just before we finish the build and
we're building with Overlay=yes, we only want the cleanup to apply
to the overlay, not the base trees, so it makes sense to run the
final cleanup operations and the finalize scripts without the base
trees mounted.

This makes using chroot finalize scripts for overlay images impossible
but this shouldn't be a huge issue.

Package removals and selinux relabelling still run with the base trees
mounted because those operations rely on various files included in the
base trees.

mkosi/__init__.py

@@ -3572,10 +3572,11 @@ def build_image(context: Context) -> None:
  if manifest:
  manifest.record_packages()
 
- clean_package_manager_metadata(context)
- remove_files(context)
  run_selinux_relabel(context)
- run_finalize_scripts(context)
+
+ clean_package_manager_metadata(context)
+ remove_files(context)
+ run_finalize_scripts(context)
 
  normalize_mtime(context.root, context.config.source_date_epoch)
  partitions = make_disk(context, skip=("esp", "xbootldr"), tabs=True, msg="Generating disk image")

mkosi/installer/__init__.py

@@ -164,9 +164,6 @@ def clean_package_manager_metadata(context: Context) -> None:
  """
  subdir = context.config.distribution.package_manager(context.config).subdir(context.config)
 
- if context.config.overlay:
- return
-
  if context.config.clean_package_metadata == ConfigFeature.disabled:
  return