[Build 3060] K8S : Ingress : When service getting removed and added back, haproxy config is not getting updated

Description:
When the service behind the Ingress is getting deleted and readded back with the same name (automatically get created with different clusterIP), Load balancer haproxy config is not getting updated in agent. Haproxy backend still pointing to old service reference. Observing a traceback in contrail-kube-manager.log

Steps:
1. Create Service
2. Create Ingress with service
3. Delete the Service
4. Add the service back with same name.

Output
-------
1. Service is created
-------------------------
[root@5b7s18 ~]# kubectl get svc
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes 10.96.0.1 <none> 443/TCP 8h
my-service 10.102.238.154 <none> 80/TCP 7m

2. Ingress is created
------------------------
[root@5b7s18 ~]# kubectl get ing
NAME HOSTS ADDRESS PORTS AGE
test-ingress * 80 6m
[root@5b7s18 ~]# kubectl get ing -o=custom-columns=NAME:.metadata.name,CLUSTER-IP:.metadata.annotations.clusterIP,EXTERNAL-IP:.metadata.annotations.externalIP
NAME CLUSTER-IP EXTERNAL-IP
test-ingress 10.47.255.248 10.87.117.251

Haproxy config in Agent
-------------------------
global
        daemon
        user haproxy
        group haproxy
        log /dev/log local0
        log /dev/log local1 notice
        tune.ssl.default-dh-param 2048
        ssl-default-bind-ciphers ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:!aNULL:!MD5:!DSS
        ulimit-n 200000
        maxconn 65000
        stats socket /var/lib/contrail/loadbalancer/haproxy/e86aa14f-2a52-11e7-a674-0cc47aa89e64/haproxy.sock mode 0666 level user

defaults
        log global
        retries 3
        option redispatch
        timeout connect 5000
        timeout client 300000
        timeout server 300000

frontend e3cd0c9c-d856-40ff-9813-7b2a77b61b2d
        option tcplog
        bind 10.47.255.248:80
        mode http
        option forwardfor
        acl 914e7571-b33c-4e24-8c0b-37e1f27cfd7a_path path /testpath
        use_backend 914e7571-b33c-4e24-8c0b-37e1f27cfd7a if 914e7571-b33c-4e24-8c0b-37e1f27cfd7a_path

backend 914e7571-b33c-4e24-8c0b-37e1f27cfd7a
        mode http
        balance roundrobin
        option forwardfor
        server 73716d04-a99f-4dbe-8845-7836b1c1902f 10.102.238.154:80 weight 1

3. Delete the service
----------------------

[root@5b7s18 ~]# kubectl delete svc
error: resource(s) were provided, but no name, label selector, or --all flag specified
[root@5b7s18 ~]# kubectl delete svc my-service
service "my-service" deleted
[root@5b7s18 ~]#
[root@5b7s18 ~]#

4. Adding the service back but got created with diffrent clusterIP
--------------------------------------------------------------------
[root@5b7s18 ~]# kubectl create -f svc.yaml
service "my-service" created
[root@5b7s18 ~]# kubectl get svc
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes 10.96.0.1 <none> 443/TCP 8h
my-service 10.100.196.88 <none> 80/TCP 4s

Haproxy config in agent
-------------------------
global
        daemon
        user haproxy
        group haproxy
        log /dev/log local0
        log /dev/log local1 notice
        tune.ssl.default-dh-param 2048
        ssl-default-bind-ciphers ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:!aNULL:!MD5:!DSS
        ulimit-n 200000
        maxconn 65000
        stats socket /var/lib/contrail/loadbalancer/haproxy/e86aa14f-2a52-11e7-a674-0cc47aa89e64/haproxy.sock mode 0666 level user

defaults
        log global
        retries 3
        option redispatch
        timeout connect 5000
        timeout client 300000
        timeout server 300000

frontend e3cd0c9c-d856-40ff-9813-7b2a77b61b2d
        option tcplog
        bind 10.47.255.248:80
        mode http
        option forwardfor
        acl 914e7571-b33c-4e24-8c0b-37e1f27cfd7a_path path /testpath
        use_backend 914e7571-b33c-4e24-8c0b-37e1f27cfd7a if 914e7571-b33c-4e24-8c0b-37e1f27cfd7a_path

backend 914e7571-b33c-4e24-8c0b-37e1f27cfd7a
        mode http
        balance roundrobin
        option forwardfor
        server 73716d04-a99f-4dbe-8845-7836b1c1902f 10.102.238.154:80 weight 1>>> still poiting to old IP

Traceback
-----------
The above is a description of an error in a Python program. Here is
the original traceback:

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/kube_manager/vnc/vnc_kubernetes.py", line 337, in vnc_process
    self.endpoints_mgr.process(event)
  File "/usr/lib/python2.7/dist-packages/kube_manager/vnc/vnc_endpoints.py", line 301, in process
    self.vnc_endpoint_add(uid, name, namespace, event)
  File "/usr/lib/python2.7/dist-packages/kube_manager/vnc/vnc_endpoints.py", line 250, in vnc_endpoint_add
    for port in ports:
TypeError: 'NoneType' object is not iterable