This patch refactors the previous object method on the scheduler report
client _compute_node_inventory() to being a module-level function called
_compute_node_to_inventory_dict(). The spurious top-level 'inventories'
key is removed from the returned dict and the payload for PUT
/r-p/{uuid}/inventories is constructed explicitly now.
Refactors the unit tests for the report client that handle inventory to
remove unnecessary mocking and correct some improper stub values that
were being masked by the mocks.
Change-Id: I70e5b649e59598b1fe356fa401769e8a7ce60c72
310e4dcbd8