This patch adds /proc/net/ip_conntrack, /proc/net/ip_conntrack_expect and
/proc/net/stat/ip_conntrack files to keep old programs using them working.
The /proc/net/ip_conntrack and /proc/net/ip_conntrack_expect files show only
IPv4 entries, the /proc/net/stat/ip_conntrack shows global statistics.
Signed-off-by: Patrick McHardy <kaber@trash.net>
