fix for upstream gompd changes

client/mpd/djrandom.go

@@ -60,6 +60,13 @@ func (s *DJRandomSong) SampleRate() float64 {
 	return 44100
 }
 
+func (s *DJRandomSong) Duration() int {
+	if s.audiofile != nil {
+		return int(s.audiofile.Duration)
+	}
+	return 0
+}
+
 func (s *DJRandomSong) URL() string {
 	return fmt.Sprintf("djrandom://%s", s.Id.String())
 }