Description of problem:

This can easily be reproduced on Azure given that egressip assignment and detachment is very slow
there.

a) Assign an EgressIP to a node. 
b) Wait until everything settles.
c) Edit the egressIP object and change its IP address.
d) Watch the egressip object and cloudprivateipconfigs. The old address will be detached and the cloudprivateipconfig will be removed.
e) Wait for the exact the moment when "assigned egressIPs" is empty in the egressip status (old CNCC IP was deleted, the CNCC tries to create the new IP address already).
f) While the CNCC tries to attach the new IP, and while "assigned egressips" is still empty in the egressip's status, quickly edit the egressip object again and change its ip address to a new value.

You will see the following:

0728 11:17:56.114041       1 client.go:781]  "msg"="transacting operations"  "database"="OVN_Northbound" "operations"="[{Op:insert Table:NAT Row:map[external_ids:{GoMap:map[name:egressip]} external_ip:10.0.129.10 logical_ip:10.129.2.14 logical_port:{GoSet:[k8s-ci-ln-nlnwi9k-1d09d-w5kh9-worker-centralus1-dszz9]} options:{GoMap:map[stateless:false]} type:snat] Rows:[] Columns:[] Mutations:[] Timeout:<nil> Where:[] Until: Durable:<nil> Comment:<nil> Lock:<nil> UUIDName:u2596996597} {Op:mutate Table:Logical_Router Row:map[] Rows:[] Columns:[] Mutations:[{Column:nat Mutator:insert Value:{GoSet:[{GoUUID:u2596996597}]}}] Timeout:<nil> Where:[where column _uuid == {a846c4e9-9c8a-41fe-befb-62c864bc1e88}] Until: Durable:<nil> Comment:<nil> Lock:<nil> UUIDName:}]"
I0728 11:17:56.117685       1 egressip.go:1423] Patching status on EgressIP egressip: [{ci-ln-nlnwi9k-1d09d-w5kh9-worker-centralus1-dszz9 10.0.129.10}]
I0728 11:19:12.419395       1 obj_retry.go:1514] Creating *factory.egressIPPod openshift-marketplace/certified-operators-wq55n took: 28.9µs
I0728 11:20:08.422899       1 egressip.go:1423] Patching status on EgressIP egressip: []
I0728 11:20:08.430849       1 egressip.go:1539] Successful assignment of egress IP: 10.0.129.11 on node: &{egressIPConfig:0xc0030af9e0 mgmtIPs:[[10 129 2 2]] allocations:map[] isReady:true isReachable:true isEgressAssignable:true name:ci-ln-nlnwi9k-1d09d-w5kh9-worker-centralus1-dszz9}
E0728 11:20:15.158012       1 egressip.go:1551] No matching host found for EgressIP: egressip
I0728 11:20:15.158113       1 event.go:285] Event(v1.ObjectReference{Kind:"EgressIP", Namespace:"", Name:"egressip", UID:"", APIVersion:"", ResourceVersion:"", FieldPath:""}): type: 'Warning' reason: 'NoMatchingNodeFound' No matching nodes found, which can host any of the egress IPs: [10.0.129.12] for object EgressIP: egressip
I0728 11:21:05.770252       1 egressip.go:1423] Patching status on EgressIP egressip: []
I0728 11:23:31.500358       1 egressip.go:1539] Successful assignment of egress IP: 10.0.129.13 on node: &{egressIPConfig:0xc0030af9e0 mgmtIPs:[[10 129 2 2]] allocations:map[] isReady:true isReachable:true isEgressAssignable:true name:ci-ln-nlnwi9k-1d09d-w5kh9-worker-centralus1-dszz9}




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