[Listener] Do not use directly TIMESTAMP fields

Since struct timeval is now abstracted by TIMESTAMP, we must not use the
structure fields (tv_sec, tv_usec) anymore.

infrastructure-centred/owlps-listener/owlps-listenerd.c

@@ -632,8 +632,7 @@ void read_packet(u_char *args, const struct pcap_pkthdr *header,
   couple.start_time = header->ts ; // Capture time is in the pcap header
   // Transmission time on the mobile is unknown (unless the packet is
   // an explicit request):
-  couple.request_time.tv_sec = 0 ;
-  couple.request_time.tv_usec = 0 ;
+  bzero(&couple.request_time, sizeof(TIMESTAMP)) ;
   // Blank position data:
   couple.direction = 0 ;
   couple.x_position = 0 ;