Recently, kubectl drain has been refactored to be consumeable
as a library. Currently, if a pod cannot be evicted due
to PDBs, we will leak a goroutine.
This commit ensures the goroutine always exists.
Related-bug: https://github.com/kubernetes/kubernetes/issues/81333
Kubernetes-commit: 0e8998a040efe5dd82592911e739fe2e2258cfa3