Misc: vers_setup_select() Item_field ctor fix

Related to #150

Author: kevgs

sql/sql_select.cc

@@ -827,24 +827,13 @@ int vers_setup_select(THD *thd, TABLE_LIST *tables, COND **where_expr,
  dst_cond= &table->on_expr;
  }
 
- Field *fstart= table->table->vers_start_field();
- Field *fend= table->table->vers_end_field();
+ const char *fstart= table->table->vers_start_field()->field_name;
+ const char *fend= table->table->vers_end_field()->field_name;
 
- Item *row_start= NULL;
- Item *row_end= NULL;
- if ((table->is_derived() && !table->is_recursive_with_table()) ||
- table->join_columns)
- {
- row_start= newx Item_field(thd, &slex->context, table->db, table->alias,
- fstart->field_name);
- row_end= newx Item_field(thd, &slex->context, table->db, table->alias,
- fend->field_name);
- }
- else
- {
- row_start= newx Item_field(thd, &slex->context, fstart);
- row_end= newx Item_field(thd, &slex->context, fend);
- }
+ Item *row_start=
+ newx Item_field(thd, &slex->context, table->db, table->alias, fstart);
+ Item *row_end=
+ newx Item_field(thd, &slex->context, table->db, table->alias, fend);
  Item *row_end2= row_end;
 
  if (table->table->versioned_by_sql())