The lint subcommand does not always find the correct files.
I am testing this with fedpkg lint which uses the rpkg implementation
(i.e. does not override with its own implementation).
It seems that the lint subcommand always searches for files
from paths defined in DIstGitLayout.
This can fail in multiple ways:

• If the layout is something else than DistGitLayout,
  thec correct files are not found.
  In particular, setting results_dir = subdir in the config file
  changes the layout to DistGitResultsDirLayout.
• The mockbuild subcommand has completely different idea about result file paths.
  Since (at least for fedpkg, mockbuild is the recommended approach,
  the lint subcommand's utility decreases significantly.

My expectation would be that the resulting rpm and srpm
are always linted when the lint subcommand is called,
no matter what config and subcommands were previously used to build them.