Use a client interface instead of a concrete type

Aids testing

plugin/cmd/kube-scheduler/app/server.go

@@ -121,7 +121,7 @@ func Run(s *options.SchedulerServer) error {
 	rl, err := resourcelock.New(s.LeaderElection.ResourceLock,
 		s.LockObjectNamespace,
 		s.LockObjectName,
-		kubecli,
+		kubecli.Core(),
 		resourcelock.ResourceLockConfig{
 			Identity:      id,
 			EventRecorder: recorder,