ref: Fix the mounttable test with the new RPC system.

Change-Id: I00cef898b18d2c997c04f824e86a5b07ca99a33b
diff --git a/cmd/mounttable/impl_test.go b/cmd/mounttable/impl_test.go
index 8786897..ddb997e 100644
--- a/cmd/mounttable/impl_test.go
+++ b/cmd/mounttable/impl_test.go
@@ -106,7 +106,7 @@
 	ctx, shutdown := test.V23Init()
 	defer shutdown()
 
-	ctx, server, err := v23.WithNewDispatchingServer(ctx, "", new(dispatcher))
+	_, server, err := v23.WithNewDispatchingServer(ctx, "", new(dispatcher))
 	if err != nil {
 		t.Fatalf("NewServer failed: %v", err)
 	}