Merge zippy.cornsilk.net:/home/cmiller/work/mysql/41gca

    Old clients send null-terminated string as password; new clients send

    the size (1 byte) + string (not null-terminated). Hence in case of empty

    password both send '\0'.

    Cast *passwd to an unsigned char, so that it doesn't extend the sign for

    *passwd > 127 and become 2**32-127 after casting to uint.

  */

  uint passwd_len= thd->client_capabilities & CLIENT_SECURE_CONNECTION ?

    *passwd++ : strlen(passwd);

    (uchar)(*passwd++) : strlen(passwd);

  db= thd->client_capabilities & CLIENT_CONNECT_WITH_DB ?

    db + passwd_len + 1 : 0;

  uint db_len= db ? strlen(db) : 0;