resolve UPDATE fields belonged to VIEWs as Item_field (instead of Item_ref) in prepared statements, too (BUG#4999)


mysql-test/r/view.result:
  Test of view updatebility in prepared statement
mysql-test/t/view.test:
  Test of view updatebility in prepared statement
sql/sql_prepare.cc:
  resolve UPDATE fields belonged to VIEWs as Item_field (instead of Item_ref) in prepared statements, too