[development] update.php and postgres 7.4

[Barry Jaspan]

Brenda,

> Who is testing upgrades against pg8.0??

I developed the D5 -> D6 upgrade patch concurrently for pg 8 and mysql
(in fact, I tested pg8 first).  I also developed the pg8 Schema API
code in database-pgsql.inc and the pg schema inspection code in
schema.module.  

I regularly check the results of a clean install and a D5 to D6
upgrade for both databases, using the schema.module to verify database
schema consistency.  Of course, that is different than actually
testing Drupal's full functionality.

Thanks,

Barry