Getting conntrack+nat helpers to work with 2.6.11

2.6.11 is out for a number of days, and we still don't have the conntrack/nat helpers from patch-o-matic ported to Rusty's latest conntrack/nat helper infrastructure changes.

It turns out that there are more changes necessary than I though initially. It's strange that nat helpers now don't have a separate expectfn() anymore, only the expectation has one. So I guess at least for talk, we'll have to call back into ip_conntrack_talk.c from ip_nat_talk.c.

With some luck I'll be finished by tomorrow and can again concentrate on the fun stuff like active-active support for ct_sync.