privacybydesign/irmago: revocation.go; 28 LoC

Found a possible issue in [privacybydesign/irmago](https://www.github.com/privacybydesign/irmago) at [revocation.go](https://github.com/privacybydesign/irmago/blob/2691b66ca19a8b62b809ef300c36fbaa4ef8d2e8/revocation.go#L723-L750)

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 id is reassigned at line 735

[Click here to see the code in its original context.](https://github.com/privacybydesign/irmago/blob/2691b66ca19a8b62b809ef300c36fbaa4ef8d2e8/revocation.go#L723-L750)

Click here to show the 28 line(s) of Go which triggered the analyzer.

```go
for id, s := range settings {
if !s.Authority {
if s.Server && s.RevocationServerURL == "" {
return errors.Errorf("revocation server mode for %s requires URL to be configured", id.String())
}
} else {
s.Server = true
if s.RevocationServerURL != "" {
return errors.Errorf("revocation authority mode for %s cannot be combined with URL", id.String())
}
}
if s.Server {
t = &id
}
if s.SSE {
urls, err := updateURL(id, rs.conf, settings)
if err != nil {
return err
}
if rs.close == nil {
rs.close = make(chan struct{})
rs.events = make(chan *sseclient.Event)
go rs.handleSSEUpdates()
}
url := fmt.Sprintf("%s/revocation/%s/updateevents", urls[0], id.String())
go rs.listenUpdates(id, url)
}
}

```

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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: 2691b66ca19a8b62b809ef300c36fbaa4ef8d2e8