MDEV-12684 Show what config file a sysvar got a value from

change get_one_option() prototype to pass the filename and
not to pass the redundant optid.

client/mysqlshow.c

@@ -289,10 +289,10 @@ are shown.");
 
 
 static my_bool
-get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
-	       char *argument)
+get_one_option(const struct my_option *opt, char *argument,
+               const char *filename __attribute__((unused)))
 {
-  switch(optid) {
+  switch(opt->id) {
   case 'v':
     opt_verbose++;
     break;