Currently we report the full inventory for available nodes, and an empty
inventory for nodes that are deployed to or otherwise unavailable.
Reporting an empty inventory for deployed nodes has 2 bad consequences:
1. Nova tries deleting the inventory for Placement, which fails, because
the resources are still in use. This results in nasty warnings.
2. When adding a resource class to a deployed node, it does not get into
inventory, and thus does not get to Placement. It results in an error
later on, when the custom resource class is not found.
This patch fixes the latter problem by
1. Always reporting the custom resource class for deployed nodes, if present.
2. Reporting VCPUS/memory/disk in exactly the same amount, as it is configured
in the ironic node's properties.
As a side effect, the warnings are no longer shown for deployed nodes.
They still appear, however, for nodes during cleaning.
Partial-Bug: #1710141
Change-Id: I2fd1e4a95f000da19864e75299afa51527697101