Fix ComponentHarnes that was using instance from root export that was…

… removed

src/test-utils/ComponentHarness.ts

@@ -4,10 +4,10 @@ import { parse as urlParse } from 'url';
 import * as qs from 'qs';
 import { RootModel } from 'racer';
 
-import { instance as derby } from '..';
 import { AppForClient } from '../App';
 import { AppForServer } from '../AppForServer';
 import { Component, ComponentConstructor, extendComponent, createFactory } from '../components';
+import { DerbyForClient } from '../Derby';
 import { PageForClient } from '../Page';
 
 export interface RenderOptions {
@@ -20,6 +20,8 @@ export class PageForHarness extends PageForClient {
   html?: any;
 }
 
+const derby = new DerbyForClient();
+
 export class AppForHarness extends AppForClient {
   _harness: any;
   _pages: PageForHarness[];