It is the first step to replace using tests.utils with openstack.common.test.
All these tests don't use mock objects, stubs, config files and use only
BaseTestCase class.

Change-Id: I511816b5c9e6c5c34ebff199296ee4fc8b84c672
bp: common-unit-tests

This library can be used in novaclient, keystoneclient,
glanceclient, and other client projects. The library
contains common code and uses python-requests for
HTTP communication.

Features:
* reissue authentication request for expired tokens;
* pluggable authentication;
* rich exceptions hierarchy.

This code partially comes from:
* python-keystoneclient/keystoneclient/base.py;
* python-novaclient/novaclient/auth_plugin.py;
* python-novaclient/novaclient/extension.py;
* python-novaclient/tests/fakes.py.

Partially implements: blueprint common-client-library

Change-Id: Ic8b466a57554018092c31c6d6b3ea62f181d7cef

These exceptions can be used in novaclient, keystoneclient,
glanceclient, and other client projects.

Concept of this file comes from cloudservers/exceptions.py
and novaclient/exceptions.py. HTTP exceptions were rewritten.

Partially implements: blueprint common-client-library

Change-Id: I9e17d855f7c26284ce66b13515aa4a0b8855347a