=BG= fix error in example syntax - use {} for named exports from ember-qunit

As pointed out by @GerritWanderer and @rjackson.
See https://github.com/stefanpenner/ember-cli/pull/894#issuecomment-45203037
Merge pull request #921 from bguiz/patch-2

fix error in example syntax - use {} for named exports from ember-qunit