Allow instance name to be parsed from start-slapd
    
    The admin server CGIs need to be able to easily parse the
    instance name from the start-slapd script.  Recent format
    changes have caused the existing parsing to break, so this
    patch makes the parsing of the instance name easier.
    
    To deal with the change in start-slapd format for an upgraded
    instance, I have changed the setup code to regenerate all of
    the instance scripts during an upgrade instead of simply adding
    missing scripts.  This is needed for any bug fix that modifies
    a script template to work for an upgraded instance.  I also
    added code to write the instance sysconfig script during upgrade
    if it doesn't exist already.  We don't want to overwrite this
    file if it already exists since it's designed for local changes
    to be made to it.