Reversing a change that incorrectly describes OVS configuration.

This reverts part of commit I9430afa843cc44694b7aca11793ec0fb640b49c6,
specifically removing lines 485-495 and reinstating lines
486-492 that they replaced. The suggested OVS configuration causes
all VMs to be placed in a single port group, in which case, no
Neutron configuration would function properly.

Change-Id: I35e0907d87b34dcd09863176b80ff434c3df171b
backport: havana
Closes-Bug: #1285448
Merge "Reversing a change that incorrectly describes OVS configuration."