Move MidonetInterfaceDriver and use mm-ctl

* Change the plug method in MidonetInterfaceDriver to use mm-ctl
* Move MidonetInterfaceDriver to interface.py
* adapt interface driver midonet unit tests to mm-ctl

Change-Id: Ib6cfbc212b793fa939cad17017c0b2b8b0a5b7fb
Closes-Bug: #1245797
Merge "Move MidonetInterfaceDriver and use mm-ctl"