socat: security bump to version 2.0.0-b8

Fixes:
CVE-2015-1379 - signal handler implementations are not async-signal-safe
and can cause crash or freeze of socat processes.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>