Style: garbage Copy_field member

Author: midenok

sql/field.h

@@ -4258,7 +4258,6 @@ class Copy_field :public Sql_alloc {
  uint from_length,to_length;
  Field *from_field,*to_field;
  String tmp;// For items
- MYSQL_TIME now; // Used for sys_trx_start
 
  Copy_field() {}
  ~Copy_field() {}