Add new attributes to EIPAssociation resource

AllocationId
NetworkInterfaceId

The EIP resource also now supports the Domain property, which when set
creates the resource using neutron networking. (Neutron networking is
required for all VPC operations.)

The EIP test covers the new functionality as well as some of the old
using both nova and neutron.

Fixes bug #1164865
Fixes bug #1164866

Change-Id: I7ad7fba8ed6f8a584fc2ca00aaf80144c5274134
Merge "Add new attributes to EIPAssociation resource"