rgw.py: refactor configure

Extend the rados pool configuration options to
specify all pools (if desired).
Also, reordered zone and region configuration
so that they're configure (per client) in
this order: zone, region, set default region

Signed-off-by: Joe Buck <jbbuck@gmail.com>
rgy.py: make log_(data|metadata) configurable

The log_data and log_metadata are made configurable
via the YAML file and default to false
(meaning neither data nor metadata operations are
logged).

Signed-off-by: Joe Buck <jbbuck@gmail.com>