Move `prepare_repo_settings` after the git directory has been set up in
`test-read-cache.c`. The git directory settings must be initialized to
properly assign repo settings using the worktree-level git config.
Signed-off-by: Victoria Dye <vdye@github.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>