Fix assert_match error of "should unbind mustache templates" in HjsTemplateTest

[htwroclau]

I'll try to fix the test failure of "should unbind mustache templates" case in HjsTemplateTest.

test failure

Failure:
HjsTemplateTest#test_should_unbind_mustache_templates [/XXX/yyy/ember-rails/test/hjstemplate_test.rb:31]:
Expected /function .*unbound|"name":"unbound"|\[\\"unbound\\"\]/m to match "Ember.TEMPLATES[\"hairy\"] = Ember.HTMLBars.template({\"id\":null,\"block\":\"{\\\"symbols\\\":[],\\\"statements\\\":[[0,\\\"This is a great \\\"],[6,\\\"img\\\"],[10,\\\"src\\\",[26,[[25,\\\"unbound\\\",[[20,[\\\"image\\\"]]],null]]]],[7],[8],[0,\\\"\\\\n\\\"]],\\\"hasEval\\\":false}\",\"meta\":{\"moduleName\":\"hairy\"}});\n".