Automatic merge from submit-queue (batch tested with PRs 66665, 66707, 66596). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

fix kubelet npe panic on device plugin return zero container
Signed-off-by: bingshen.wbs <bingshen.wbs@alibaba-inc.com>



**What this PR does / why we need it**:
Fix kubelet panic when device plugin return zero containers. Panic logs like follows:
```
Jul 17 12:50:24 iZwz9bqgzuo4i8qu435zk8Z kubelet[25815]: /workspace/anago-v1.10.4-beta.0.68+5ca598b4/src/k8s.io/kubernetes/_output/dockerized/go/src/
k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:51
Jul 17 12:50:24 iZwz9bqgzuo4i8qu435zk8Z kubelet[25815]: /workspace/anago-v1.10.4-beta.0.68+5ca598b4/src/k8s.io/kubernetes/_output/dockerized/go/src/
k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:65
Jul 17 12:50:24 iZwz9bqgzuo4i8qu435zk8Z kubelet[25815]: /workspace/anago-v1.10.4-beta.0.68+5ca598b4/src/k8s.io/kubernetes/_output/dockerized/go/src/
k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:72
Jul 17 12:50:24 iZwz9bqgzuo4i8qu435zk8Z kubelet[25815]: E0717 12:50:24.726856   25815 runtime.go:66] Observed a panic: "index out of range" (runtime error
: index out of range)
```

**Release note**:

```
NONE
```