[bug]: garbage of ingress-controller-leader-kube-system.lb-xxx configmap

[hicaistar]

Is this a BUG REPORT or FEATURE REQUEST?:

Uncomment only one, leave it on its own line:

/kind bug

/kind feature

What happened:

There are a lot of configmaps like ' ingress-controller-leader-kube-system.lb-xxx' in 'kube-system'. As I know, it is created by ingress controller, so each loadbalancer instance will generate one. We need to delete them when the loadbalancer instance was deleted.

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

/cc @hanxueluo