Fix tests for Cisco Plugin and move the to proper place to make runable

Cisco Plugin for Quantum has a number of unit tests which have the following problems:

1) They are placed inside quantum/plugins/cisco/tests directory and thus they are not executed by OpenStack CI test runner

2) Several tests are outdated and thus broken. (This can be seen by running "python
quantum/plugins/cisco/run_tests.py" )

To make plugin code more stable it would be nice to:

1) Fix all tests in quantum/plugins/cisco/tests

2) Move them to quantum/tests/unit/cisco to make test runner "see" and execute them and thus prevent possible harmful code modifications in code which they are intended to cover