Minimal upgrade docs for 2.3

[Russ Allbery]

I've added this section to the beginning of NEWS in the current tree;
please let me know what else should be included.  The exact command lines
to rebuild the history and overview files would also be good to include.

Upgrading from 2.2 to 2.3

    This section is still a work in progress and is not complete.  There
    may be additional things to watch out for not listed here; if you run
    across any, please let inn-bugs at isc.org know about them.

    Simply doing a make update is not sufficient to upgrade.  For one,
    several of the scripts that live in the samples directory have been
    updated, and some of those updates are required to work with INN 2.3.
    (It's possible that this will be fixed before the final 2.3 release.)

    The history file format changed between 2.2 and 2.3, as did the
    overview format.  Regardless of whether you were using the storage API
    or traditional spool under 2.2, you'll need to rebuild your overview
    and history files.  The program to use to rebuild the history file is
    makedbz, not makehistory.  makehistory is used to rebuild the overview
    database.

    For a reader machine, nnrp.access has been replaced by readers.conf.
    There currently isn't a program to convert between the old format and
    the new format (if you'd like to contribute one, it would be welcomed
    gratefully).  You may need to look over the sample readers.conf and
    readers.conf(5) to understand how to write a file equivalent to your
    current nnrp.access.

    The flags for overchan have changed, plus you probably don't want to
    run overchan at all any more.  Letting innd write overview data itself
    results in somewhat slower performance, but is more reliable and has a
    better failure mode under high loads.  Writing overview data directly
    is the default, so in a normal upgrade from 2.2 to 2.3 you'll want to
    comment out or remove your overchan entry in newsfeeds and set
    useoverchan to false in inn.conf.

-- 
Russ Allbery (rra at stanford.edu)         <URL:http://www.eyrie.org/~eagle/>