refs: make refs/bisect/* per-worktree
We need the place we stick refs for bisects in progress to not be
shared between worktrees. So we make the refs/bisect/ hierarchy
per-worktree.
The is_per_worktree_ref function and associated docs learn that
refs/bisect/ is per-worktree, as does the git_path code in path.c
The ref-packing functions learn that per-worktree refs should not be
packed (since packed-refs is common rather than per-worktree).
Since refs/bisect is per-worktree, logs/refs/bisect should be too.
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>