fixed RegisterConnectHandler function

internal/peermgr/handler.go

@@ -42,9 +42,9 @@ func (swarm *Swarm) registerMsgHandler(messageType pb.Message_Type, handler inte
 }
 
 func (swarm *Swarm) RegisterConnectHandler(handler ConnectHandler) error {
-	//swarm.lock.Lock()
-	//defer swarm.lock.Unlock()
-	//swarm.connectHandlers = append(swarm.connectHandlers, handler)
-	//return nil
-	panic("Unimplemented!")
+	swarm.lock.Lock()
+	defer swarm.lock.Unlock()
+	swarm.connectHandlers = append(swarm.connectHandlers, handler)
+	return nil
+	//panic("Unimplemented!")
 }