The provided name argument is always constant and valid in every
caller's context, so no need to have an array of PATH_MAX chars to copy
it into when a simple pointer will do.  Unfortunately that means getting
rid of wascally wabbits too.

The 'error' field is also unused.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>