MDEV-13397 MariaDB upgrade fail when using default_time_zone

don't try to set default time zone in --bootstrap,
this generally cannot be done, as timezone tables aren't loaded.
and bootstrap scripts don't need it anyway.

mysql-test/t/bootstrap.test

@@ -105,3 +105,12 @@ use test;
 EOF
 --exec $MYSQLD_BOOTSTRAP_CMD --ignore-db-dirs='some_dir' --ignore-db-dirs='some_dir' < $MYSQLTEST_VARDIR/tmp/bootstrap_9969.sql >> $MYSQLTEST_VARDIR/tmp/bootstrap.log 2>&1
 --remove_file $MYSQLTEST_VARDIR/tmp/bootstrap_9969.sql
+
+#
+# MDEV-13397 MariaDB upgrade fail when using default_time_zone
+#
+--write_file $MYSQLTEST_VARDIR/tmp/bootstrap_9969.sql
+use test;
+EOF
+--exec $MYSQLD_BOOTSTRAP_CMD --default-time-zone=Europe/Moscow < $MYSQLTEST_VARDIR/tmp/bootstrap_9969.sql >> $MYSQLTEST_VARDIR/tmp/bootstrap.log 2>&1
+--remove_file $MYSQLTEST_VARDIR/tmp/bootstrap_9969.sql

sql/tztime.cc

@@ -1663,7 +1663,7 @@ my_tz_init(THD *org_thd, const char *default_tzname, my_bool bootstrap)
   {
     /* If we are in bootstrap mode we should not load time zone tables */
     return_val= time_zone_tables_exist= 0;
-    goto end_with_setting_default_tz;
+    goto end_with_cleanup;
   }
 
   /*