setup: stop using `the_repository` in `verify_filename()`

setup: stop using `the_repository` in `verify_filename()`

Stop using `the_repository` in `verify_filename()` and instead accept
the repository as a parameter. The injection of `the_repository` is thus
bumped one level higher, where callers now pass it in explicitly.

Signed-off-by: Patrick Steinhardt <redacted>
Signed-off-by: Junio C Hamano <redacted>