prepare_linked_checkout() respects git-checkout's --quiet flag, however,
the plan is to relocate "git checkout --to" functionality to "git
worktree add", and git-worktree does not (yet) have a --quiet flag.
Consequently, make prepare_linked_checkout() unconditionally verbose to
ease eventual code movement to worktree.c.
(A --quiet flag can be added to git-worktree later if there is demand
for it.)
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>