ply-utils: Get rid of unused old code,
drop function ply_get_max_open_fds, ply_close_open_fds, ply_close_all_fds; These codes is created long time ago, and not been used in current project. So remove them to keep the source clean.
drop function ply_get_max_open_fds, ply_close_open_fds, ply_close_all_fds; These codes is created long time ago, and not been used in current project. So remove them to keep the source clean.