Fix formatting for ICMP. Closes #572778

Author: Chris Taylor <ctaylor@debian.org>
--- a/iptstate.cc
+++ b/iptstate.cc
@@ -793,7 +793,7 @@ void initialize_maxes(max_t &max, flags_
   /*
    * The proto header is 5, so we can't drop below 6.
    */
-  max.proto = 3;
+  max.proto = 4;
   /*
    * "ESTABLISHED" is generally the longest state, we almost always have
    * several, so we'll start with this. It also looks really bad if state
