It is possible to delete a source compute service which has
pending migration-based allocations and servers in VERIFY_RESIZE
status. Doing so deletes the compute service and compute node
but orphans the source node resource provider along with its
resource allocations held by the migration record while there
is a pending resized server.
This adds a simple cold migrate test which deletes the source
compute service while the server is in VERIFY_RESIZE status and
then tries to confirm the resize which fails.