Description of problem:
After reboot egress node,  lr-policy-list was not correct, some duplicate records or missed internal IPs

Version-Release number of selected component (if applicable):
4.9.0-0.nightly-2021-08-19-184748

How reproducible:
Frequently 

Steps to Reproduce:
1. Lable 3 egress nodes and create one egressip object
...
spec:
    egressIPs:
    - 172.31.248.103
    - 172.31.248.104
    - 172.31.248.105
    namespaceSelector:
      matchLabels:
        name: test
    podSelector: {}
  status:
    items:
    - egressIP: 172.31.248.103
      node: compute-1
    - egressIP: 172.31.248.104
      node: compute-2
    - egressIP: 172.31.248.105
      node: compute-0
...
2.Create two namespace, and label ns name=test, then create 10 pods for each namespace.

3. Check the lr-policy-list 

sh-4.4#  ovn-nbctl lr-policy-list ovn_cluster_router  | grep "100 "
       100                             ip4.src == 10.128.2.45         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.46         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.47         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.48         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.49         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.50         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.31         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.32         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.33         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.34         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.35         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.51         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.52         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.53         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.54         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.55         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.56         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.57         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.58         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.59         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
sh-4.4#  ovn-nbctl lr-policy-list ovn_cluster_router  | grep "100 " | wc -l
20

4. Then reboot egress node compute-0

5. After the node back to ready, check lr-policy-list  again

Actual results:
There some duplicate records. Like  ,one is with 3 internal IPs, one is with 2 internal IPs
      100                             ip4.src == 10.131.0.56         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
      100                             ip4.src == 10.131.0.56         reroute                100.64.0.6, 100.64.0.7

Some missed internal IP. Only two internal IPs, if curl from the related pods, it will use 2 egress nodes, even we have 3 egress nodes available.
100                             ip4.src == 10.131.0.57         reroute                100.64.0.6, 100.64.0.7

$ oc rsh -n test2 test-rc-sbp6f
~ $  while true; do curl 172.31.249.80:9095;sleep 2; echo ""; done;
172.31.248.104
172.31.248.104
172.31.248.103
172.31.248.104
172.31.248.103
172.31.248.103
172.31.248.104
172.31.248.104
172.31.248.103
172.31.248.104
172.31.248.104
172.31.248.104
172.31.248.104
172.31.248.104
172.31.248.104
.....
172.31.248.104
172.31.248.104
172.31.248.103

sh-4.4# ovn-nbctl lr-policy-list ovn_cluster_router  | grep "100 "
       100                             ip4.src == 10.128.2.45         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.46         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.47         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.48         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.49         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.128.2.50         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.31         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.32         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.33         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.34         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.129.2.35         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.51         reroute                100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.51         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.52         reroute                100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.52         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.53         reroute                100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.53         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.54         reroute                100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.54         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.55         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.55         reroute                100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.56         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.56         reroute                100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.57         reroute                100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.58         reroute                100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.58         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.59         reroute                100.64.0.6, 100.64.0.7
       100                             ip4.src == 10.131.0.59         reroute                100.64.0.5, 100.64.0.6, 100.64.0.7

sh-4.4# ovn-nbctl lr-policy-list ovn_cluster_router  | grep "100 " | wc -l
28

Expected results:
After egress nodes reboot, lr-policy-list should have records as before reboot nodes.

Additional info:
Moreover, after delete two namespaces, test and test2, that means all test pods gone, there are still some lr-policy-list left.

workaround is restart ovn-kubemaster pods.