As a follow-up to r2494, the ordering of the environment initialization
steps has been changed:
1. First, load the config, and make that work even if there's no config file,
as the logger initialization needs the config.
2. Initialize the logger, as some components might want to use it
3. Initialize the components, as they are now needed in order to get
the proper db backend
4. Only then, eventually create the environment and the db (init_db)
All the unit-tests pass again.
Still, there are probably issues with the trac/db/postgresql.py backends,
as I didn't test them.
