system-traffic.at: Skip the 'ICMP6 Related' test if nc is missing.
Test fails is 'nc' is not available, it should be skipped instead.
Fixes: ("System Tests: Enhance NAT tests.")
@@ -6432,6 +6432,7 @@ AT_CLEANUP
AT_SETUP([conntrack - IPv6 ICMP6 Related with SNAT])
AT_SKIP_IF([test $HAVE_TCPDUMP = no])
+AT_SKIP_IF([test $HAVE_NC = no])
CHECK_CONNTRACK()
CHECK_CONNTRACK_NAT()
OVS_TRAFFIC_VSWITCHD_START()
