Comment 5 for bug 1717916

@Matt thanks for looking on this.

I confirm this test was working before, but during last time (I can't say for sure near cutting pike release) we start experiencing problems with races in scheduler. We increased scheduler/host_subset_size to 9999 recently (https://review.openstack.org/#/q/I0874fe3b3628cb3e662ee01f24c4599247fdc82d) to stabilize concurrent tests, but now test_schedule_to_all_nodes is failing frequently and looks like it is the same race in scheduler.