VPN: set IFF_NO_PI on TUN interface.

Packet info header (struct tun_pi) was required to support IPv6
in kernel prior to 2.6.26. Setting IFF_NO_PI will remove the header
from the packets sent/recieved via TUN file descriptor, so now they
are just raw IP packets.

Change-Id: I0b4ae9db23d3bc10995a00eb053527b499ad6eb6
1 file changed