ipops: add a comment about autogenerated files from ragel

modules/ipops/ip_parser.c

@@ -1,3 +1,7 @@
+/*
+ * Warning: This file is auto generated from a ragel syntax (ip_parser.rl),
+ * do not change it!
+ */
 
 #line 1 "ip_parser.rl"
 #include "ip_parser.h"

modules/ipops/ip_parser.h

@@ -1,3 +1,8 @@
+/*
+ * Warning: This file is auto generated from a ragel syntax (ip_parser.rl),
+ * do not change it!
+ */   
+
 #ifndef ip_parser_h
 #define ip_parser_h