Don't close logfile_fp before running JavaScript externals

This would've prevented some JS log functions from writing to the node.log file
(which gets concatented onto the daily "system" log files).

This just came up via code review while looking into Keyop's reported error:
term Node 2 !ERROR 9 (Bad file descriptor) in main.cpp line 4606 (node_thread)
     truncating "logfile" access=0

This is likely unrelated since the "logfile" is immediately re-opened after
executing the external program/script.

src/sbbs3/xtrn_sec.cpp

@@ -1382,7 +1382,7 @@ bool sbbs_t::exec_xtrn(uint xtrnnum, bool user_event)
 	         , user_event ? "user event" : "program"
 	         , cfg.xtrn[xtrnnum]->name);
 	logline("X-", str);
-	if (cfg.xtrn[xtrnnum]->cmd[0] != '*' && logfile_fp != NULL) {
+	if (cfg.xtrn[xtrnnum]->cmd[0] != '?' &&  cfg.xtrn[xtrnnum]->cmd[0] != '*' && logfile_fp != NULL) {
 		fclose(logfile_fp);
 		logfile_fp = NULL;
 	}