Merge branch 'js/import-tars-do-not-make-phony-files-from-pax-headers'

The import-tars importer (in contrib/fast-import/) used to create
phony files at the top-level of the repository when the archive
contains global PAX headers, which made its own logic to detect and
omit the common leading directory ineffective, which has been
corrected.

* js/import-tars-do-not-make-phony-files-from-pax-headers:
  import-tars: ignore the global PAX header