Fix Coverity 1491741 and 1491742.

src/logging.c

@@ -291,7 +291,7 @@ static int log__vprintf(unsigned int priority, const char *fmt, va_list va)
 					log_line_pos = (size_t)snprintf(log_line, sizeof(log_line), "Time error");
 				}
 			}else{
-				log_line_pos = (size_t)snprintf(log_line, sizeof(log_line), "%d", (int)db.now_real_s);
+				log_line_pos = (size_t)snprintf(log_line, sizeof(log_line), "%" PRIu64, (uint64_t)db.now_real_s);
 			}
 			if(log_line_pos < sizeof(log_line)-3){
 				log_line[log_line_pos] = ':';

src/sys_tree.c

@@ -239,7 +239,7 @@ void sys_tree__update(void)
 			&& db.now_s - db.config->sys_interval >= last_update){
 
 		uptime = db.now_s - start_time;
-		len = (uint32_t)snprintf(buf, BUFLEN, "%d seconds", (int)uptime);
+		len = (uint32_t)snprintf(buf, BUFLEN, "%" PRIu64 " seconds", (uint64_t)uptime);
 		db__messages_easy_queue(NULL, "$SYS/broker/uptime", SYS_TREE_QOS, len, buf, 1, 60, NULL);
 
 		sys_tree__update_clients(buf);