Correct issue where flood detection could become unreliable

The static 'pos' variable in check_flooding() would not stay in sync with the number of entries in
flood_list after clean_flood_list() was called.  This meant that check_flooding() would always end up
removing all previous entries if it tried to add a new one.

Fix this by removing the tracking of number of flood_list entries, and just removing stale ones (older
than /SET FLOOD_RATE).

include/struct.h

@@ -1015,7 +1015,7 @@ typedef struct	flood_stru
 	int	type;
 	char	flood;
 	unsigned long	cnt;
-	time_t	start;
+	struct timeval	start;
 }	Flooding;