Merge branch 'nd/init-core-worktree-in-multi-worktree-world'

"git init" tried to record core.worktree in the repository's 'config' file when GIT_WORK_TREE environment variable was set and it was different from where GIT_DIR appears as ".git" at its top, but the logic was faulty when .git is a "gitdir:" file that points at the real place, causing trouble in working trees that are managed by "git worktree". This has been corrected. * nd/init-core-worktree-in-multi-worktree-world: init: kill git_link variable init: do not set unnecessary core.worktree init: kill set_git_dir_init() init: call set_git_dir_init() from within init_db() init: correct re-initialization from a linked worktree