A cleanup for MDEV-16542 Fix ALTER TABLE FORCE to upgrade temporal types

Removing redundant space character after the data type comment
in SHOW CREATE TABLE, so the output changes from e.g.:

  a TIME /* mariadb-5.3 */  DEFAULT NULL

to

  a TIME /* mariadb-5.3 */ DEFAULT NULL

This is a prerequisite for MDEV-19906.

sql/sql_show.cc

@@ -2119,7 +2119,7 @@ int show_create_table(THD *thd, TABLE_LIST *table_list, String *packet,
     DBUG_EXECUTE_IF("sql_type",
                     packet->append(" /* ");
                     packet->append(field->type_handler()->version().ptr());
-                    packet->append(" */ ");
+                    packet->append(" */");
                     );
 
     if (field->has_charset() && !(sql_mode & (MODE_MYSQL323 | MODE_MYSQL40)))