emissary: Request with "x-ambassador-test-allow: probably" is 200 OK

Describe the bug I followed the rate limiting tutorial using minikube, but I don’t see 429 status codes as expected:

$ curl -i -H "x-ambassador-test-allow: probably" $AMBASSADORURL/qotm/quote/1
HTTP/1.1 200 OK
content-type: application/json
content-length: 147
server: envoy
date: Thu, 24 Jan 2019 09:30:47 GMT
x-envoy-upstream-service-time: 65

{"hostname":"qotm-7c6cccd985-4s8kg","ok":true,"quote":"A late night does not make any sense.","time":"2019-01-24T09:30:47.705604","version":"1.3"}

To Reproduce Create a new Kubernetes cluster and install Ambassador quay.io/datawire/ambassador:0.50.0-rc5.

$ minikube delete
$ minikube start
Starting local Kubernetes v1.13.2 cluster...
$ kubectl apply -f https://www.getambassador.io/yaml/ambassador/ambassador-rbac.yaml
$ kubectl apply -f - <<<'
apiVersion: v1
kind: Service
metadata:
  name: ambassador
spec:
  selector:
    service: ambassador
  type: NodePort
  ports:
    - port: 80
  # Propagate the original source IP of the client.
  externalTrafficPolicy: Local
'
$ AMBASSADORURL=$(minikube service --url ambassador)

Then deploy a qotm service:

$ kubectl apply -f - <<<'
---
apiVersion: v1
kind: Service
metadata:
  name: qotm
  annotations:
    getambassador.io/config: |
      ---
      apiVersion: ambassador/v0
      kind:  Mapping
      name:  qotm_mapping
      prefix: /qotm/
      service: qotm
spec:
  selector:
    app: qotm
  ports:
  - port: 80
    name: http-qotm
    targetPort: http-api
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: qotm
spec:
  replicas: 1
  strategy:
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: qotm
    spec:
      containers:
      - name: qotm
        image: datawire/qotm:1.2
        ports:
        - name: http-api
          containerPort: 5000
        readinessProbe:
          httpGet:
            path: /health
            port: 5000
          initialDelaySeconds: 30
          periodSeconds: 3
        resources:
          limits:
            cpu: "0.1"
            memory: 100Mi
'

and ratelimit service:

$ kubectl apply -f - <<<'
---
apiVersion: v1
kind: Service
metadata:
  name: example-rate-limit
  annotations:
    getambassador.io/config: |
      ---
      apiVersion: ambassador/v0
      kind: RateLimitService
      name: ratelimit
      service: "example-rate-limit:5000"
spec:
  type: ClusterIP
  selector:
    app: example-rate-limit
  ports:
  - port: 5000
    name: http-example-rate-limit
    targetPort: http-api
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: example-rate-limit
spec:
  replicas: 1
  strategy:
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: example-rate-limit
    spec:
      containers:
      - name: example-rate-limit
        image: agervais/ambassador-ratelimit-service:1.0.0
        imagePullPolicy: Always
        ports:
        - name: http-api
          containerPort: 5000
        resources:
          limits:
            cpu: "0.1"
            memory: 100Mi
'

Finally, add rate_limits to qotm service:

$ kubectl apply -f - <<<'
---
apiVersion: v1
kind: Service
metadata:
  name: qotm
  annotations:
    getambassador.io/config: |
      ---
      apiVersion: ambassador/v0
      kind: Mapping
      name: qotm_mapping
      prefix: /qotm/
      service: qotm
      rate_limits:
        - descriptor: A test case
          headers:
            - "x-ambassador-test-allow"
spec:
  type: ClusterIP
  selector:
    app: qotm
  ports:
  - port: 80
    name: http-qotm
    targetPort: http-api
'

Expected behavior I expect 429 status code as described in the tutorial.

Versions (please complete the following information):

• Ambassador: 0.50.0-rc5
• Kubernetes environment: Minikube v0.33.1
• Version: v1.13.2