Make Resource names suitable for merge/include

In nova-compute-instance.yaml, we need to use resource names that are
unique within the entire set of resources that may be merged or
included. However, we need the instance resource name to _match_ the
one in overcloud-source.yaml so that its own access policies can
function.

Without this change we will not have unique users and Metadata access
keys/policies for compute and controller.

Change-Id: Iebde7e6adede4984f4f693cf2d57b6fadb8be558