busybox

truncate: do not die when a file doesn't exist and no-create flag is on

Additionally, open(2) failures do not make the program die immediately.
This makes the behavior of the program match coreutils more closely.

function                                             old     new   delta
truncate_main                                        161     221     +60

Signed-off-by: Ari Sundholm <ari@tuxera.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>