Description of problem:
After modifying the cluster ingress.config.openshift.io .spec.domain the operator will be degraded with condition:
    - lastTransitionTime: "2019-07-08T11:59:25Z"
      message: 'failed handling the route: route has no host: &v1.Route{TypeMeta:v1.TypeMeta{Kind:"",
        APIVersion:""}, ObjectMeta:v1.ObjectMeta{Name:"oauth-openshift", GenerateName:"",
        Namespace:"openshift-authentication", SelfLink:"/apis/route.openshift.io/v1/namespaces/openshift-authentication/routes/oauth-openshift",
        UID:"<uid>", ResourceVersion:"<version>", Generation:0,
        CreationTimestamp:v1.Time{Time:time.Time{wall:0x0, ext:63698183501, loc:(*time.Location)(0x2b32340)}},
        DeletionTimestamp:(*v1.Time)(nil), DeletionGracePeriodSeconds:(*int64)(nil),
        Labels:map[string]string{"app":"oauth-openshift"}, Annotations:map[string]string(nil),
        OwnerReferences:[]v1.OwnerReference(nil), Initializers:(*v1.Initializers)(nil),
        Finalizers:[]string(nil), ClusterName:""}, Spec:v1.RouteSpec{Host:"", Subdomain:"",
        Path:"", To:v1.RouteTargetReference{Kind:"Service", Name:"oauth-openshift",
        Weight:(*int32)(0xc420545e18)}, AlternateBackends:[]v1.RouteTargetReference(nil),
        Port:(*v1.RoutePort)(0xc4205b0ea0), TLS:(*v1.TLSConfig)(0xc420ca7d40), WildcardPolicy:"None"},
        Status:v1.RouteStatus{Ingress:[]v1.RouteIngress{v1.RouteIngress{Host:"oauth-openshift.<old domain>",
        RouterName:"default", Conditions:[]v1.RouteIngressCondition{v1.RouteIngressCondition{Type:"Admitted",
        Status:"True", Reason:"", Message:"", LastTransitionTime:(*v1.Time)(0xc4205b0f00)}},
        WildcardPolicy:"None", RouterCanonicalHostname:"<old domain>"}}}}'
      reason: OperatorSyncLoopError
      status: "True"


The route is:
$ oc get route -o yaml
apiVersion: v1
items:
- apiVersion: route.openshift.io/v1
  kind: Route
  metadata:
    creationTimestamp: "2019-07-08T11:51:41Z"
    labels:
      app: oauth-openshift
    name: oauth-openshift
    namespace: openshift-authentication
    resourceVersion: "7007259"
    selfLink: /apis/route.openshift.io/v1/namespaces/openshift-authentication/routes/oauth-openshift
    uid: c03c510a-a176-11e9-8f81-0a580a800041
  spec:
    host: oauth-openshift.<old domain>
    port:
      targetPort: 6443
    subdomain: ""
    tls:
      insecureEdgeTerminationPolicy: Redirect
      termination: passthrough
    to:
      kind: Service
      name: oauth-openshift
      weight: 100
    wildcardPolicy: None
  status:
    ingress:
    - conditions:
      - lastTransitionTime: "2019-07-08T11:51:41Z"
        status: "True"
        type: Admitted
      host: oauth-openshift. <old domain>
      routerCanonicalHostname: <old domain>
      routerName: default
      wildcardPolicy: None
kind: List
metadata:
  resourceVersion: ""
  selfLink: ""

Version-Release number of selected component (if applicable):
4.1.2 (may happen in newer versions)

How reproducible:
Always

Steps to Reproduce:
1. Start with a cluster is working as expected
2. "oc edit ingress.config.openshift.io cluster" and modify spec.domain
3. Check the route and the operator yaml dump.

Actual results:
Operator is degraded, and the old route is maintained

Expected results:
Route will be deleted and recreated with the expected value

Additional info:
As a workaround delete the route oauth-openshift in the project openshift-authentication