Remove deprecated vconfig support

This removes the deprecated vconfig support which I'm not sure
ever worked properly to begin with. The
neutron.ovs.public_interface_raw_device heat metadata parameter
can also be removed since it is no longer used for anything.

Once this lands we should follow up and land a Heat templates
patch to remove the neutron.ovs.public_interface_raw_device
parameter there as well. I've filed this bug to track that:

Partial-bug: #1386910

Change-Id: Ia712d5e5d6de4aa41857b12a8d218dd9ec41be61
Merge "Remove deprecated vconfig support"