This function was never used since its inception in
dd05ea1
(test case for transitive info/alternates, 2006-05-07).
Which is just as well, since it mutates the repo state in a
way that would invalidate further tests, without cleaning up
after itself. Let's get rid of it so that nobody is tempted
to use it.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>