test: fix conntracks test

In some old distros -m state doesn't work correctly and test fails
because test output diverges from expected results. Here we replace
obsoleted -m state with -m conntrack.

travis-ci: success for series starting with [v2,1/2] test: replace cat in Makefiles with awk
Signed-off-by: Vitaly Ostrosablin <vostrosablin@virtuozzo.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/zdtm/static/conntracks

@@ -29,7 +29,7 @@ do_start()
 
 	do_or_fail "can't install a state match" \
 		iptables -A INPUT \
-		-m state --state RELATED,ESTABLISHED -j ACCEPT
+		-m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
 
 	do_or_fail "can't list the loaded iptables" \
 		iptables -L \> "$statefile"