Add 'instance_name' to bm_nodes table so that baremetal driver is able
to return the names of all instances it believes are still running.
Previously, baremetal.driver.list_instances was fetching all allocated
instances from baremetal database, then calling VirtAPI to get the
instance name. This would raise an InstanceNotFound exception for
deleted instances. This prevented ComputeManager from ever detecting
a running-but-deleted baremetal instance, and could leave baremetal
instances in an undeletable state.
Fixes bug 1096723.
Change-Id: Ifae532e8e70e97e48c589608cb3c7000bb6a7609
2eef56505b