Fix order-dependent jasmine failure in contacts_collection_spec.js

This was failing if `app.aspect` got set by another spec than ran before it (such as one of the other specs in the same file, when run in a different order).

spec/javascripts/app/collections/contacts_collection_spec.js

@@ -21,6 +21,7 @@ describe("app.collections.Contacts", function(){
     });
 
     it("should compare the username if app.aspect is not present", function() {
+      delete app.aspect;
       expect(this.collection.comparator(this.con1, this.con3)).toBeLessThan(0);
     });