[MINOR] stick_table: add support for "conn_cum" data type.

This one can be parsed on the "stick-table" after with the "store"
keyword. It will hold the number of connections matching the entry,
for use with ACLs or anything else.
diff --git a/include/types/stick_table.h b/include/types/stick_table.h
index dda9edb..a43c110 100644
--- a/include/types/stick_table.h
+++ b/include/types/stick_table.h
@@ -41,11 +41,13 @@
 
 /* The types of extra data we can store in a stick table */
 enum {
+	STKTABLE_DT_CONN_CUM,     /* cumulated number of connections */
 	STKTABLE_DATA_TYPES       /* Number of data types, must always be last */
 };
 
 /* stick_table extra data. This is mainly used for casting or size computation */
 union stktable_data {
+	unsigned int conn_cum;
 };
 
 #define stktable_data_size(type) (sizeof(((union stktable_data*)0)->type))