busybox

sort: check global flags on fallback sort

Sort now performs global reverse on fallback sort if -r is set. Before
only key local flags were checked.

function                                             old     new   delta
compare_keys                                         712     738     +26

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>