fixed error handling in subselect fix_field


mysql-test/r/subselect.result:
  test of name resolution
mysql-test/t/subselect.test:
  test of name resolution
sql/item.cc:
  fixed couple of bugs in field/reference name resolution.
sql/item_subselect.cc:
  fixed error handling
sql/mysql_priv.h:
  fixed couple of bugs in field/reference name resolution.
sql/sql_base.cc:
  fixed couple of bugs in field/reference name resolution.
sql/sql_select.cc:
  new find_item_in_list interface