PostgreSQL 8.x defaults

[Craig Boston]

I recently installed some PostgreSQL 8.2 servers (and upgraded some from
8.1), and it reminded me of a few lingering nits in our port that bug
me.  Mostly the port seems that it can't make up its mind about VACCUM
strategy.

* We have a patch that sets autovacuum = yes in the default
  postgresql.conf.  However, it leaves the default stats_row_level = no,
  so autovacuum doesn't actually run.
* Despite trying to turn on autovacuum, the port installs
  periodic/daily/502.pgsql, which runs VACUUM (not even VACUUM ANALYZE)
  by default nightly.

It seems to me that we should pick one or the other -- either

1. Fully enable autovacuum and default to daily_pgsql_vacuum_enable="NO"
   to avoid a superfluous cron job

or

2. Leave the periodic job enabled and not tease people with an
   ineffectual autovacuum = yes in postgresql.conf.

Of the two I'd prefer the former, but that's just my opinion.

Craig