to pick up the first part fix of bug49396.

    ------------------------------------------------------------------------
    r6471 | calvin | 2010-01-15 17:43:27 -0600 (Fri, 15 Jan 2010) | 4 lines

    branches/5.1: fix bug#49396: main.innodb test fails in embedded mode

    Change replace_result by using $MYSQLD_DATADIR. Tested in both embedded
    mode and normal server mode.
    ------------------------------------------------------------------------