Handle setting a new default route.

In a production environment, the overcloud, which has it's metadata
server as default route until we kill file injection, may not be the
default route, so we need to be able to influence routing.

Change-Id: I698682183a301141e224e5713a49b23f8e6c863e
Setup CD overcloud public networking.

Change-Id: I02f02bc5a99d8fc847fd47e9f16e14d2c5ec8270
Pass in the CD overcloud floating net details.

So you know, it works.

Change-Id: Ic46609ecfed89e4d46af7a1f361147c4dcbfe85d