On older OpenBSD releases you especially should not have been
using /dev/random, nowdays due to changes all the device nodes
are actually all the same so either way this code can be simplified
to not special case OpenBSD in vlc_rand_init().
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>
(manually cherry picked from 3fc4af487dc23113a3c9602e1022f464f3992601)