Fixed typo in doc/source

There was a typo in the Authentication section of the usage.rst
file.

This has been fixed, along with some lining up of comments in the
test code to make it easier to read.

Change-Id: I342a286055246beaeadc7e763d3b75bd17c32a60
Reverse fix for 1323866 as it regressed trove CLI

Trove CLI appears to be broken (fresh checkout, devstack as well as
openstack gate). All commands fail with

ERROR: __init__() got an unexpected keyword argument 'http_log_debug'

Correcting the obvious place where this appears to be an issue is
causing additional failures and as it is time-critical to get this
back up and running, I'm proposing a reversal of the change from
3c47a1855b7ee1345dadfb00ae90a6279b7c424e while that change is
completely reworked.

I will ping trove core for an approval on this and if I don't get an
approval, I'll fast track this reversal.

Change-Id: Icac028cfafac57c7e3ef03d4277ae2b7833bf58f
Partial-Bug: 1391840
Merge "Reverse fix for 1323866 as it regressed trove CLI"
Merge "Fixed typo in doc/source"