RelationSetCommand.Run() does not check all errors

[Ian Booth]

There is a bug in RelationSetCommand.Run().

 settings, err := r.Settings()
 for k, v := range c.Settings {
  if v != "" {
   settings.Set(k, v)
  } else {
   settings.Delete(k)
  }
 }

The error from r.Settings() is not checked. This can lead to a panic if there is an issue. See bug 1356500.