Yuanhong Peng fc7d1ce752 Ignore layer does not exist error from docker images ...

Fix #31350

As we can see in `daemon.Images()`, there is a gap between
`allImages = daemon.imageStore.Map()` and `l, err :=
daemon.layerStore.Get(layerID)`, so images which still exist when we hit
`allImages = daemon.imageStore.Map()` may have already been deleted when we hit
`l, err := daemon.layerStore.Get(layerID)`.

```
	if danglingOnly {
        	allImages = daemon.imageStore.Heads()
	} else {
        	allImages = daemon.imageStore.Map()
	}

	...

	for id, img := range allImages {
		...

		layerID := img.RootFS.ChainID()
        	var size int64
	        if layerID != "" {
        	        l, err := daemon.layerStore.Get(layerID)
                	if err != nil {
                        	return nil, err
                	}
```

Signed-off-by: Yuanhong Peng <pengyuanhong@huawei.com>
Upstream-commit: 2b9694c29e3bbbce23f0c4009f908a23c115c598
Component: engine

2017-03-16 09:21:51 +08:00

..

engine

Ignore layer does not exist error from docker images

2017-03-16 09:21:51 +08:00