order of entries in admin docs

["Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com>]

I was just looking for something in the admin docs, and it seems like
the ordering of sections is sub-optimal.

17. Operating System Environment
18. Server Configuration
19. Database Roles and Privileges
20. Managing Databases
21. Client Authentication

Seems that Client Authentication should come right after Server
Configuration.  After all, how is someone going to handle roles and
database creation before they've authenticated?  Is there some reason
for the order that I'm missing?  Is it an easy change?  I'd be happy
to try and make a patch for something like that if there's a chance of
it getting through / my figuring out how to do it in the docs.