Downgrade go version for travis, remove go 1.13 error wrapping

.travis.yml

@@ -1,7 +1,7 @@
 language: go
 go:
   # - "1.11.x" At minimum the code should run make check on the latest two go versions in the default linux environment provided by Travis.
-  - "1.13.x"
+  - "1.12.x"
 
 dist: xenial
 

pkg/router/route_group.go

@@ -448,7 +448,7 @@ func (rg *RouteGroup) waitForCloseLoop(waitTimeout time.Duration) error {
 
 	select {
 	case <-closeCtx.Done():
-		return fmt.Errorf("close loop timed out: %w", closeCtx.Err())
+		return fmt.Errorf("close loop timed out: %v", closeCtx.Err())
 	case <-closeDoneCh:
 	}
 

pkg/router/router.go

@@ -422,7 +422,7 @@ func (r *router) handleClosePacket(ctx context.Context, packet routing.Packet) e
 	}
 
 	if err := rg.handleClosePacket(closeCode); err != nil {
-		return fmt.Errorf("error handling close packet with code %d by route group with descriptor %s: %w",
+		return fmt.Errorf("error handling close packet with code %d by route group with descriptor %s: %v",
 			closeCode, &desc, err)
 	}