Currently if http requests are not correctly mocked, behaviour of the
unit tests will depend on what happens to be running on localhost.
Jobs like gate-os-collect-config-python27-ubuntu-xenial are currently
broken because discover requests are being made to localhost and
something has change in the environment to cause test failure.
This change does the following:
- replace unit tests addresses from 127.0.0.1 to 192.0.2.1 (TEST-NET-1)
- fix mocking of tests which now stall because 192.0.2.1 isn't accessable
- change the mocking approach to keystoneclient.discover.Discover to
a simple stub class
Change-Id: I6d9450d6854b9f50dac0f55f54f1ea1d579a27ac