Introduce random server faking mechanism.
Introduce random server faking mechanism.

This patch introduces a new server faking mechanism to support
multiple servers faking.

Server names and ids can be generated randomly, and use APIs in
class FakeServer to get one or more servers.

Change-Id: Ic54f3bf7c77294dc7dfb9acdbf4a721eb5eef6af
Implements: blueprint osc-unit-test-framework-improvement

redhat-openstack/python-openstackclient,openstack/python-openstackclient,dtroyer/python-openstackclient,BjoernT/python-openstackclient,BjoernT/python-openstackclient,dtroyer/python-openstackclient,openstack/python-openstackclient,redhat-openstack/python-openstackclient