opencontainers/image-tools: image/image.go; 44 LoC

Found a possible issue in [opencontainers/image-tools](https://www.github.com/opencontainers/image-tools) at [image/image.go](https://github.com/opencontainers/image-tools/blob/22b993e8aa1c17e1cbe5d251b7b4f937a665966a/image/image.go#L95-L138)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first issue it finds, so please do not limit your consideration to the contents of the below message.

> reference to desc is reassigned at line 96

[Click here to see the code in its original context.](https://github.com/opencontainers/image-tools/blob/22b993e8aa1c17e1cbe5d251b7b4f937a665966a/image/image.go#L95-L138)

Click here to show the 44 line(s) of Go which triggered the analyzer.

```go
for _, desc := range descs {
d := &desc
if err = validateDescriptor(d, w, validRefMediaTypes); err != nil {
return err
}

if d.MediaType == validRefMediaTypes[0] {
m, err := findManifest(w, d)
if err != nil {
return err
}

if err := validateManifest(m, w); err != nil {
return err
}
}

if d.MediaType == validRefMediaTypes[1] {
index, err := findIndex(w, d)
if err != nil {
return err
}

if err := validateIndex(index, w); err != nil {
return err
}

if len(index.Manifests) == 0 {
fmt.Println("warning: no manifests found")
return nil
}

for _, manifest := range index.Manifests {
m, err := findManifest(w, &manifest)
if err != nil {
return err
}

if err := validateManifest(m, w); err != nil {
return err
}
}
}
}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: 22b993e8aa1c17e1cbe5d251b7b4f937a665966a