Send notification for any updates to instance objects

Before objects, a notification would be sent for any change to an
instance and the notifications.send_update method would handle any
filtering that needed to be done prior to sending the event.

Currently, the instance objects code is pre-filtering the notification
by only checking if vm_state or task_state changed which is a
regression.

This patch removes the filter in the instance objects code so that
notifications are again sent for any changes to the instance and lets
the notifications.send_update method handle the event as it did before.

Closes-Bug: #1220186

Change-Id: Ib6ceedfe55b021be0fe7fa910e97d46c0cd8f0cd
Merge "Send notification for any updates to instance objects"