Add expected IDs to router.interface.* notifications

Fixes bug 1160431

The router.interface.{create|delete} notifications are intended to be
consumed by ceilometer, but did not include the router or tenant IDs
in the RPC message payload. Ceilometer requires both these data for
metering purposes.

The missing UUIDs are now provided in the notifications.

Change-Id: I1ca6e1d5377100a0549293e0bdff0182711c750f