This tests the PDB status update path in DisruptionController and
asserts that conflicting writes (with eviciton handler) are handled
gracefully.
This adds the client-go fake.Clientset into our tests, because that is
the layer required for injecting update failures.
This also adds a TestMain so that DisruptionController logs can be
enabled during test. e.g.,
go test ./pkg/controller/disruption -v -args -v=4
c8d937c5f1