send_stats_to_secmod() is called as soon as possible

This allows us to send the client assigned IP to radius server
as soon as it is available, rather than waiting a full interim_update
cycle.

src/worker-vpn.c

@@ -418,7 +418,7 @@ void vpn_server(struct worker_st *ws)
 			      "could not disable system calls, kernel might not support seccomp");
 		}
 	}
-	ws->session_start_time = ws->last_stats_msg = time(0);
+	ws->session_start_time = time(0);
 
 	if (ws->remote_addr_len == sizeof(struct sockaddr_in))
 		ws->proto = AF_INET;