Remove unit tests that are no longer run.

A long time ago, quantum/tests/unit became the home for all unit
tests, but these ones in the Cisco plugin directory got left
behind. They have suffered bit-rot and need to be removed.

Also:
- Move the fake Nexus driver to new home.
- Filed new bugs to track the task of improving unit test coverage of
  Cisco plugin code.

Fixes: bug #1174311
Change-Id: I372e24aebbe1804e5b6ce62984bfd76b030a44b1
Merge "Remove unit tests that are no longer run."