Comment 8 for bug 1379201

The upstream commit that caused this change is:
73f156a6e8c1074ac6327e0abd1169e95eb66463

The new interface is:
void ip_select_ident(struct sk_buff *skb, struct sock *sk)

Commits in ubuntu kernel trees:
3.2/precise: 519331a6416a517ca93a88d8cffc662562f15320
3.13/trusty/precise: 015c969fca9e99d90cda9b399391ac563b4dbc37