ingress.class enhancement for debugging.

[snoby]

This is a suggestion for improvement. I spent some time debugging why when running an ingress with the ingress.class annotation for class set, why my ingresses were not being added to my ingress controller. Receiving this error message in the logs:

7 controller.go:168] ignoring add for ingress echomap based on annotation kubernetes.io/ingress.class

didn't help because it didn't tell me what the ingress controller was actually seeing in the annotation. As it turns out my problem was because the ingress had an annotation of:
ingress. kubernetes.io/ingress.class: "internal"
instead of
kubernetes.io/ingress.class: "internal"

I would recommend that the isValid function print what it sees as the annotion:

 ingEventHandler := cache.ResourceEventHandlerFuncs{
        AddFunc: func(obj interface{}) {
            addIng := obj.(*extensions.Ingress)
            if !class.IsValid(addIng, ic.cfg.IngressClass, ic.cfg.DefaultIngressClass) {
                glog.Infof("ignoring add for ingress %v based on annotation %v", addIng.Name, class.IngressKey)
                return
            }

because right now the class.IngressKey just prints kubernetes.io/ingress.class

[aledbf]

didn't help because it didn't tell me what the ingress controller was actually seeing in the annotation. As it turns out my problem was because the ingress had an annotation of:

Good point. Added for next beta