chewong: fix: do not hardcode nginx image URL in rc e2e test case

JobBuild
95841
10-23 20:38
cb78e889
10-23 20:37
pull-kubernetes-bazel-build 1319739686930878464
pull-kubernetes-bazel-test 1319739686956044288
pull-kubernetes-conformance-kind-ga-only-parallel 1319739687111233536
pull-kubernetes-conformance-kind-ipv6-parallel 1319739686972821504
pull-kubernetes-dependencies 1319739686997987328
pull-kubernetes-e2e-gce-100-performance 1319739687752962048
pull-kubernetes-e2e-gce-ubuntu-containerd 1319739687018958848
pull-kubernetes-e2e-kind 1319739687065096192
pull-kubernetes-e2e-kind-ipv6 1319739687086067712
pull-kubernetes-integration 1319739687039930368
pull-kubernetes-node-e2e 1319739687132205056
pull-kubernetes-typecheck 1319739688587628544
pull-kubernetes-verify 1319739689430683648