Give etcd client logger a name

Logic copied from https://github.com/etcd-io/etcd/blob/v3.5.4/client/v3/client.go#L374

Signed-off-by: Nic Cope <nicc@rk0n.org>

Kubernetes-commit: f54d2606336e2e8130339d2a0bc04fac6906aa78

pkg/storage/storagebackend/factory/etcd3.go

@@ -86,7 +86,7 @@ func init() {
 	if err != nil {
 		l = zap.NewNop()
 	}
-	etcd3ClientLogger = l
+	etcd3ClientLogger = l.Named("etcd-client")
 }
 
 func newETCD3HealthCheck(c storagebackend.Config, stopCh <-chan struct{}) (func() error, error) {