trivial: Don't shadow built-ins

trivial: Don't shadow built-ins

* Don't use 'str', 'id', 'max', etc. as variable names
* Remove unnecessary use of six.range
* Remove unnecessary use of six.map

There is one paramter in xmlrpc that cannot be renamed as it could
break some client code. noqa this instead.

Signed-off-by: Stephen Finucane <stephenfinucane@hotmail.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>