In the next patch, we will replace a manual checking of "." or ".."
with a call to is_dot_or_dotdot() defined in dir.h. The private
function read_directory() defined in this file will conflict with
the global function declared there when we do so.
As a preparatory step, rename the private read_directory() to avoid
the name collision.
Helped-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Brian Bourn <ba.bourn@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>