mysql-test/r/ps.result:
  Better error message
mysys/my_error.c:
  Comments added
sql/item.cc:
  Moved a chunk of code from sql_prepare.cc to Item_param::set_from_user_var
sql/item.h:
  Moved a chunk of code from sql_prepare.cc to Item_param::set_from_user_var
sql/item_func.cc:
  Code cleanup
sql/mysql_priv.h:
  Code cleanup
sql/sql_class.cc:
  Code cleanup
sql/sql_parse.cc:
  use user_var_entry::val_str in PREPARE stmt FROM @var.
sql/sql_prepare.cc:
  Post-review fixes and code cleanup.
sql/sql_yacc.yy:
  Coding style fixes