ns-threat_shield: increase default icmp limit (#822)

The icmp limit could be hit if the network, or the firewall itself,
is pinging many hosts for WAN status checking or link quality monitor.

In case of normal user a firewall should be able to easily support 100 icmp packets per second.
Note the limit is not per host, but for all icmp traffic.

packages/ns-threat_shield/files/banip-defaults

@@ -14,7 +14,7 @@ delete banip.global.ban_logterm
 add_list banip.global.ban_logterm="Exit before auth from"
 add_list banip.global.ban_logterm="authentication failed for user"
 
-set banip.global.ban_icmplimit="10"
+set banip.global.ban_icmplimit="100"
 set banip.global.ban_synlimit="10"
 set banip.global.ban_udplimit="100"