The extensible resource tracker plugins were deprecated in
Ie4b6670a828d99aebfd348bd700f9f58b3e39fdb - it is now time
to remove the feature. Providers will no longer be able
to extend the resource types they want to track.
The compute node stats field is now updated every time
stats change (as it originally was before ERT). Some tests
have had stats added to the expected field in assertions
to account for this information.
Change-Id: Ia34ca9160ca34bcfa3ed56395e1b68ca802c0c51