pilgreen/drive2hugo: main.go; 57 LoC

Found a possible issue in [pilgreen/drive2hugo](https://www.github.com/pilgreen/drive2hugo) at [main.go](https://github.com/pilgreen/drive2hugo/blob/26669be48cef7ee16a7193905977e61906c160e8/main.go#L75-L131)

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 folder used in defer or goroutine at line 106

[Click here to see the code in its original context.](https://github.com/pilgreen/drive2hugo/blob/26669be48cef7ee16a7193905977e61906c160e8/main.go#L75-L131)

Click here to show the 57 line(s) of Go which triggered the analyzer.

```go
for _, folder := range config.Folders {
var q string

mod, err := modTime()
if *mPtr == true && err == nil {
q = fmt.Sprintf("mimeType = 'application/vnd.google-apps.document' and '%s' in parents and modifiedTime > '%s'", folder.Id, mod)
} else {
q = fmt.Sprintf("mimeType = 'application/vnd.google-apps.document' and '%s' in parents", folder.Id)
}

r, err := srv.Files.List().Q(q).Fields("files(name, id)").Do()
if err != nil {
log.Fatalf("Unable to retrieve files: %v", err)
}

log.Printf("%d files found in %s\n", len(r.Files), folder.Id)
if len(r.Files) > 0 {
os.MkdirAll(folder.Path, 0755)
queue := make(chan *drive.File, len(r.Files))
done := make(chan bool)

// Set up the goroutine to handle the individual files
go func() {
for {
file, more := <-queue
if more {
req, err := srv.Files.Export(file.Id, "text/plain").Download()
if err != nil {
log.Fatalf("Unable to download file: %v", err)
}

filename := filepath.Join(folder.Path, file.Name + ".md")
body, _ := ioutil.ReadAll(req.Body)

err = ioutil.WriteFile(filename, body, 0644)
if err != nil {
log.Printf("Problem writing %s: %v\n", filename, err)
} else {
log.Printf("%s ... \u2713\n", filename)
}
} else {
log.Printf("all done with folder: %s\n", folder.Id)
done <- true
return
}
}
}()

for _, file := range r.Files {
queue <- file
}

close(queue)
<- done
}
}

```

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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: 26669be48cef7ee16a7193905977e61906c160e8