And fix a bug in it that caused too-small allocations in some
circumstances.
The main demonstration of this failure was:
nodepool.tests.test_allocator.TwoLabels.test_allocator(two_nodes)
Which allocated 1,2 instead of 2,2. But the following tests also
failed:
nodepool.tests.test_allocator.TwoProvidersTwoLabels.test_allocator(four_nodes_over_quota)
nodepool.tests.test_allocator.TwoProvidersTwoLabels.test_allocator(four_nodes)
nodepool.tests.test_allocator.TwoProvidersTwoLabels.test_allocator(three_nodes)
nodepool.tests.test_allocator.TwoProvidersTwoLabels.test_allocator(four_nodes_at_quota)
nodepool.tests.test_allocator.TwoProvidersTwoLabels.test_allocator(one_node)
Change-Id: Idba0e52b2775132f52386785b3d5f0974c5e0f8e