Another FreeBSD compile fix

Apparently, on FreeBSD the sys/types.h is not included while it does
make use of types defined there. So include it manually first.

processcore/plugins/network/helper/Packet.cpp

@@ -21,6 +21,7 @@
 
 #include "Packet.h"
 
+#include <sys/types.h>
 #include <arpa/inet.h>
 #include <net/ethernet.h>
 #include <netinet/ip.h>