git: root-level license globs also match directories, vendoring unrelated folders #1428

Summary

The license auto-keep patterns dfetch adds to the sparse-checkout (licen[cs]e*,
copying*, copyright*) are written without a trailing /, so they match
directories as well as files. A repo with a root-level directory whose name
starts with licen/copying/copyright gets that whole directory vendored into
the destination, next to the requested src: subtree.

Use case

The top level has an unrelated licensecore folder. I want to fetch another folder from this repo.

Dfetch will automatically copy the toplevel licensecore folder in the vendored folder, because the folder name matches the license check.

Potential fix

Would it be possible to make the license check a bit more strict?