Ticket #47763 - winsync plugin modify is broken
    
    Description: Thanks to Carsten Grzemba for the patch.  Made minimum
    changes such as replacing the direct access to the bv_len in Slapi_Value
    with slapi_value_get_length.
    
    Note: Regarding attr_compare_equal, since there is no strong reason
    to switch to this new attr_compare_equal, we continue using the original
    code.  The newly provided code is in "#if 0".
    
    https://fedorahosted.org/389/ticket/47763
    
    Reviewed by rmeggins@redhat.com (Thanks, Rich!)
    
    (cherry picked from commit b6b7199470671315d693ddec8db7c4ffbc4a1ee8)