busybox

*: s/"/bin/sh"/DEFAULT_SHELL, run_shell() API fix, remove unneeded strdup

function                                             old     new   delta
run_shell                                            157     166      +9
su_main                                              477     470      -7
sulogin_main                                         515     503     -12

Signed-off-by: Ladislav Michl <Ladislav.Michl@seznam.cz>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>