netfilter: conntrack: place 'new' timeout in first location too

tcp, sctp and dccp trackers re-use the userspace ctnetlink states
to index their timeout arrays, which means timeout[0] is never
used.  Copy the 'new' state (syn-sent, dccp-request, ..) to 0 as well
so external users can simply read it off timeouts[0] without need to
differentiate dccp/sctp/tcp and udp/icmp/gre/generic.

The alternative is to map all array accesses to 'i - 1', but that
is a much more intrusive change.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>