VPNaaS: remove dependency on Neutron in UT

[Paul Michali]

Some of the driver unit tests mock execute() from Neutron, which creates a (brittle) dependency (as seen by a recent breakage).

The dependency can be removed, but mocking higher up, from within the *Swan process _execute() method.

In addition, there are some unit tests that are not active, due to missing test base class.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/169008

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/169008
Committed: https://git.openstack.org/cgit/openstack/neutron-vpnaas/commit/?id=65a294eebca3297db2ca33846a6058d7d36a9869
Submitter: Jenkins
Branch: master

commit 65a294eebca3297db2ca33846a6058d7d36a9869
Author: Paul Michali <email address hidden>
Date: Mon Mar 30 15:05:34 2015 +0000

    VPNaaS Remove dependency on Neutron for unit test

    Instead of mocking the execute() method from Neutron, we'll mock
    higher up, at _execute() for the *Swan process. This will isolate
    the tests from Neutron.

    Found that some DVR tests were not activated (missing BaseTestCase
    inheritance), and cleaned up a few tests.

    Change-Id: Ia7655714088f53478d4286b8f61fca77688c1ecc
    Closes-Bug: #1438259