Fix invalid import order

Updated import order as per the OpenStack import standards [1].
Modules under magnum/common/pythonk8sclient are not covered in
this patch because this code is generated via a third party
tool "swagger-codegen" which does not follows openstack
standards yet.

[1] http://docs.openstack.org/developer/hacking/#import-order-template

Change-Id: Ia87f3e797ee627bf3c04d2bae9639fd305b41b0d

magnum/tests/functional/tempest_tests/config.py

@@ -13,9 +13,9 @@
 from __future__ import print_function
 
 from oslo_config import cfg
-
 from tempest import config  # noqa
 
+
 service_available_group = cfg.OptGroup(name="service_available",
                                        title="Available OpenStack Services")