fix the issue that the lays of images doesn't have full image info.
fix the issue that the lays of images doesn't have full image info.

some of the history has body like:
```json
    {
      "v1Compatibility":
        "{\"id\":\"38c5916c333...\",\"parent\":\"bac7f0439852...\"}"
    }
```

The analyze function break directly.

Signed-off-by: jianqli <59b4f51be6d27b82126b9ccd39e73d1100a34d26@ebay.com>

anchore/anchore-engine,anchore/anchore-engine,anchore/anchore-engine