flow/predefined: fix handleARPICMPRequests
flow/predefined: fix handleARPICMPRequests

The checksum must be calculated on the echo response.

Currently it gets calculated on the received echo request,
so the response gets sent with a wrong checksum.

More strict OS, like OpenBSD, drop ICMP Packets with
a wrong checksum.

Signed-off-by: Stefan Rinkes <0befe15d1634596f149374884b67550a95381bdd@gmail.com>

intel-go/yanff,intel-go/yanff,intel-go/yanff,intel-go/yanff