mysql-test/r/auto_increment.result:
  test result
mysql-test/t/auto_increment.test:
  test case
sql/handler.cc:
  print_keydupp_error implemented
sql/handler.h:
  handler::print_keydupp_error declared
sql/share/errmsg.txt:
  error message added
sql/sql_table.cc:
  now we return different error message for auto_increment case