The function connect_work_tree_and_git_dir is declared in both submodule.h
and dir.h, such that one of them is redundant. As the function is
implemented in dir.c, drop the declaration from submodule.h
Signed-off-by: Stefan Beller <sbeller@google.com> Reviewed-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>