FillZpp: Fix maxUnavailable of StatefulSet should not less than 1

JobBuild
110069
05-16 09:04
85e3194c
05-16 09:03
pull-kubernetes-conformance-kind-ga-only-parallel 1527739437566398464 1526126042966659072
pull-kubernetes-dependencies 1527739437318934528 1526126042773721088
pull-kubernetes-e2e-gce-100-performance 1527739437717393408 1526126043088293888
pull-kubernetes-e2e-gce-ubuntu-containerd 1527739437373460480 1526126042815664128
pull-kubernetes-e2e-kind 1527739437465735168 1526126042899550208
pull-kubernetes-e2e-kind-ipv6 1527739437516066816 1526126042933104640
pull-kubernetes-integration 1527739437423792128 1526126042857607168
pull-kubernetes-node-e2e-containerd 1527739437654478848 1526126043029573632
pull-kubernetes-typecheck 1527739437759336448 1526126043130236928
pull-kubernetes-unit 1527787078056677376 1527739437608341504 1526126042996019200
pull-kubernetes-verify 1527739438996656128 1526126044430471168
pull-kubernetes-verify-govet-levee 1527739438170378240 1526126043583221760