NULL fixed
max_length fixed
layout fixed


mysql-test/r/row.result:
  NULL fixed
mysql-test/t/row.test:
  NULL fixed
sql/item.cc:
  postreview fix
sql/item.h:
  postreview fix
sql/item_cmpfunc.cc:
  layout fix
  postreview fix
  max_length fix
  NULL fixed
sql/item_cmpfunc.h:
  postreview fix
sql/item_row.cc:
  NULL fixed
sql/item_row.h:
  NULL fixed
sql/sql_class.cc:
  postreview fix