Adding api_version to FakeApp
Adding api_version to FakeApp

In order to use app.api_version['<some_service>'] we need to have the
api_version on FakeApp otherwise the test will fail.

Patch that will benefit from this:
https://review.openstack.org/#/c/572536/

Change-Id: Ibb3c548daf2a62b6c4aefb5e257372dd5c56521e

openstack/python-openstackclient,dtroyer/python-openstackclient,openstack/python-openstackclient,dtroyer/python-openstackclient