Merge pull request #48944 from liaoyw/renew-lease-errormsg

Automatic merge from submit-queue

Log error when failed to renew lease.

**What this PR does / why we need it**:

Log detailed error when leaderelection can not renew release.
It would add a little bit help to find direct reason of failing renew lease
```
E0626 15:23:06.269198   46443 leaderelection.go:263] Failed to update lock: etcdserver: request timed out
E0626 15:23:07.528206   46443 leaderelection.go:263] Failed to update lock: Operation cannot be fulfilled on endpoints "kube-scheduler": the object has been modified; please apply yo
ur changes to the latest version and try again
E0626 15:23:07.528260   46443 event.go:259] Could not construct reference to: '&v1.Endpoints{TypeMeta:v1.TypeMeta{Kind:"", APIVersion:""}, ObjectMeta:v1.ObjectMeta{Name:"", GenerateN
ame:"", Namespace:"", SelfLink:"", UID:"", ResourceVersion:"", Generation:0, CreationTimestamp:v1.Time{Time:time.Time{sec:0, nsec:0, loc:(*time.Location)(nil)}}, DeletionTimestamp:(*
v1.Time)(nil), DeletionGracePeriodSeconds:(*int64)(nil), Labels:map[string]string(nil), Annotations:map[string]string(nil), OwnerReferences:[]v1.OwnerReference(nil), Finalizers:[]str
ing(nil), ClusterName:""}, Subsets:[]v1.EndpointSubset(nil)}' due to: 'selfLink was empty, can't make reference'. Will not report event: 'Normal' 'LeaderElection' 'gd6-k8s-noah-prod0
01-master-s0004 stopped leading'
I0626 15:23:07.528391   46443 leaderelection.go:208] failed to renew lease kube-system/kube-scheduler
F0626 15:23:07.528422   46443 server.go:134] lost master
```

staging/src/k8s.io/client-go/tools/leaderelection/leaderelection.go

@@ -200,7 +200,7 @@ func (le *LeaderElector) renew() {
 			return
 		}
 		le.config.Lock.RecordEvent("stopped leading")
-		glog.Infof("failed to renew lease %v", desc)
+		glog.Infof("failed to renew lease %v: %v", desc, err)
 		close(stop)
 	}, 0, stop)
 }