pss: fixed type conversion error

Author: aperonam

pss/pss.go

@@ -705,13 +705,11 @@ func sendMsg(p *Pss, sp *network.Peer, msg *PssMsg) bool {
 //// successfully forwarded to at least one peer.
 func (p *Pss) forward(msg interface{}) error {
 	var pssMsg *PssMsg
-	switch msg.(type) {
-	case PssMsg:
-		pssMsg = msg.(*PssMsg)
-	default:
+	pssMsg, ok := msg.(*PssMsg)
+	if !ok {
 		return errors.New("cannot forward a non pssMsg pssMsg")
-
 	}
+
 	metrics.GetOrRegisterCounter("pss.forward", nil).Inc(1)
 	sent := 0 // number of successful sends
 	to := make([]byte, addressLength)