Resolves: bug 457846
    Bug Description: The Windows Sync API should have plug-in points - part 2
    Reviewed by: nkinder (Thanks!)
    Fix Description: Some additional changes to the api
    The modify callbacks were not sufficient to handle all cases.  We need to have access to the DS entry.  This changes the API to add the DS entry to the modify callbacks.  I also had to change the handling of the userAccountControl - it cannot just overwrite the value, it must set the appropriate bit in the bit mask.
    Platforms tested: RHEL5
    Flag Day: no
    Doc impact: yes - plugin guide