Adds an interface to a multihomed
endpoint. Takes 2 arguments of type node. Argument 1 is the core
node of the multihomed endpoint. Argument 2 is the interface node
to be added. Mandatory for multihomed endpoints. All interfaces
must be added after set-multihome-core is called and before
multihome-attach-agent is called.
Tom Henderson
2011-11-05