Openvswitch 2.1 removes openvswitch-controller

If you attempt to use the newer openvswitch, the install will complain
that the package openvswitch-controller is missing.

Openvswitch notices in the changelog that many people were installing
openvswitch-controller, thinking it was a necessary package. It's not.

Tested this on debian-upstart and ubuntu.

Change-Id: Ibbf0409e1cd189a1ad93f35bac03648902774008
Merge "Openvswitch 2.1 removes openvswitch-controller"