The functions init_db() and initialize_repository_version() were shared
by builtin/init-db.c and builtin/clone.c, and declared in cache.h.
Move these functions, plus their several helpers only used by these
functions, to setup.[ch].
Diff best viewed with `--color-moved`.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>