busybox: fix double free in top causing a SIGABRT storm after SIGPIPE

busybox: fix double free in top causing a SIGABRT storm after SIGPIPE

On some platforms the command 'top -n1 | head' goes very often into an
infinite loop of SIGABRT and double free()s.

Fix by applying a patch from upstream Busybox.

For a detailed explanation of the bug, see
http://lists.busybox.net/pipermail/busybox/2016-August/084555.html

Thanks to Yann for the help in finding this bug.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Cc: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>