Bugs fixed:
Security Fix: 
        If a user has access to MyISAM table
        t, that user can create a
        MERGE table m that
        accesses t. However, if the user's
        privileges on t are subsequently
        revoked, the user can continue to access
        t by doing so through
        m. If this behavior is undesirable,
        you can start the server with the new
        --skip-merge option to disable
        the MERGE storage engine.
       (Bug#15195, CVE-2006-4031)

