Fixed make_test_dist()'s permission problem once and for all.

make_test_dist()'s $destination_directory must be 755 not 700 like tempdir()
likes to create it as (Probably because I turn on the higher security setting).
So, after running tempdir() in make_test_dist() or in make_test_dist()'s caller
if you specify your own $destination_directory to make_test_dist(), you must
chmod your $destination_directoy to 755, so that a drop_priv()'ed child can
still access it if run as root with stay_root in its default off position.