[olsrd] added bind v6 only patch for json/txtinfo

When the IPV6_V6ONLY flag is not set, olsrd6 will
listen on both ports (IPv6 and IPv4). A subsequent process
running on IPv4 can't listen on the same IPv4 port and
therefor jsoninfo or txtinfo will not work anymore.

See 01c1ea4 at http://olsr.org/git/?p=olsrd.git