Fix Karma reference to jQuery.

Off a fresh install, `grunt test` fails.

```bash
Running "karma:unit" (karma) task
INFO [karma]: Karma v0.12.16 server started at http://localhost:9876/
INFO [launcher]: Starting browser Chrome
WARN [watcher]: Pattern "/Users/erictaylor/Documents/test-ember/app/bower_components/jquery/jquery.min.js" does not match any file.
WARN [watcher]: Pattern "/Users/erictaylor/Documents/test-ember/.tmp/test/spec/*.js" does not match any file.
INFO [Chrome 36.0.1985 (Mac OS X 10.9.3)]: Connected on socket W8PSYlIPKSxSYeDpxgrU with id 61192191
Chrome 36.0.1985 (Mac OS X 10.9.3) ERROR
  Uncaught Error: Could not find module jquery
  at /Users/erictaylor/Documents/test-ember/app/bower_components/ember/ember.js:251
```

`karma.config.js` references the old jquery location.

Updated `karma.config.js` to reference the updated `jquery.min.js` location.