fix(e2e): without devTools

according to https://github.com/electron/spectron/issues/174#issuecomment-319242097 this might help re error like in https://travis-ci.org/artemv/angular-electron-spectron/builds/500315009

..but this also could be node version dependent as I don't have it locally on MacOS & Node 9

e2e/main.spec.ts

@@ -22,7 +22,7 @@ describe('angular-electron App', function () {
 
   it('creates initial windows', async function () {
     const count = await client.getWindowCount();
-    expect(count).to.equal(2);
+    expect(count).to.equal(1);
   });
 
 });