yp-engineering/docker-events-hook: docker-events-hook.go; 41 LoC

Found a possible issue in [yp-engineering/docker-events-hook](https://www.github.com/yp-engineering/docker-events-hook) at [docker-events-hook.go](https://github.com/yp-engineering/docker-events-hook/blob/c6b31b080e5ec8227ee7c911a5d840e543123ff3/docker-events-hook.go#L147-L187)

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.

> range-loop variable plugin used in defer or goroutine at line 161

[Click here to see the code in its original context.](https://github.com/yp-engineering/docker-events-hook/blob/c6b31b080e5ec8227ee7c911a5d840e543123ff3/docker-events-hook.go#L147-L187)

Click here to show the 41 line(s) of Go which triggered the analyzer.

```go
for plugin, name := range plugins {
go func() {
var result string
var pluginError error

inspect, err := dockerInspect(event)
if err != nil {
glog.Errorf("couldn't inspect event: %#v", event)
return
}

call := "Api." + strings.Title(event.Status)
switch event.Status {
case "attach":
pluginError = plugin.Call(call, inspect, &result)
case "create":
pluginError = plugin.Call(call, inspect, &result)
case "delete":
pluginError = plugin.Call(call, event, &result)
case "destroy":
pluginError = plugin.Call(call, event, &result)
case "die":
pluginError = plugin.Call(call, inspect, &result)
case "kill":
pluginError = plugin.Call(call, inspect, &result)
case "resize":
pluginError = plugin.Call(call, inspect, &result)
case "start":
pluginError = plugin.Call(call, inspect, &result)
case "untag":
pluginError = plugin.Call(call, event, &result)
default:
glog.Errorf("unknown event: %v", event)
}
eventInfo(event, name, inspect, result, call)

if pluginError != nil {
glog.Errorf("plugin error: %#v", pluginError)
}
}()
}

```

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See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: c6b31b080e5ec8227ee7c911a5d840e543123ff3