tests: Replaces images used with agnhost (part 3)

Quite a few images are only used a few times in a few tests. Thus,
the images are being centralized into the agnhost image, reducing
the number of images that have to be pulled and used.

This PR replaces the usage of the following images with agnhost:

- audit-proxy
- crd-conversion-webhook
- entrypoint-tester
- inclusterclient
- iperf
- porter
- serve-hostname

test/e2e/scheduling/ubernetes_lite.go

@@ -56,7 +56,7 @@ var _ = SIGDescribe("Multi-AZ Clusters", func() {
 	})
 
 	ginkgo.It("should spread the pods of a replication controller across zones", func() {
-		SpreadRCOrFail(f, int32((2*zoneCount)+1), image)
+		SpreadRCOrFail(f, int32((2*zoneCount)+1), image, []string{"serve-hostname"})
 	})
 })
 
@@ -177,7 +177,7 @@ func checkZoneSpreading(c clientset.Interface, pods *v1.PodList, zoneNames []str
 
 // SpreadRCOrFail Check that the pods comprising a replication
 // controller get spread evenly across available zones
-func SpreadRCOrFail(f *framework.Framework, replicaCount int32, image string) {
+func SpreadRCOrFail(f *framework.Framework, replicaCount int32, image string, args []string) {
 	name := "ubelite-spread-rc-" + string(uuid.NewUUID())
 	ginkgo.By(fmt.Sprintf("Creating replication controller %s", name))
 	controller, err := f.ClientSet.CoreV1().ReplicationControllers(f.Namespace.Name).Create(&v1.ReplicationController{
@@ -199,6 +199,7 @@ func SpreadRCOrFail(f *framework.Framework, replicaCount int32, image string) {
 						{
 							Name:  name,
 							Image: image,
+							Args:  args,
 							Ports: []v1.ContainerPort{{ContainerPort: 9376}},
 						},
 					},