os-config-applier->os-apply-config for Neutron

Part of the ongoing evolution in names.

Change-Id: Ic37c302b2309fd3d262bf570f95241bd562de2b4
Permit setting ml2 flat networks in Neutron.

This is needed to deploy the ci features in the overcloud - access to
the bare metal LAN.

Change-Id: I9fa923b63033edb694720bfe5fc756a7c0fbfd2a