[specs] Fix caches-item-test by using the correct helper name

tests/integration/components/ssh-key-test.js

@@ -79,4 +79,4 @@ test('it does not delete the custom key if permissions are insufficient', functi
 
   assert.ok(Ember.isEmpty(this.$('.ssh-key-action').find('a')), 'delete link should not be displayed');
 
-});
+});

tests/unit/components/caches-item-test.coffee

@@ -1,7 +1,7 @@
 `import { test, moduleForComponent } from 'ember-qunit'`
 
 moduleForComponent 'caches-item', 'CachesItemComponent', {
-  needs: ['helper:format-time', 'helper:mb']
+  needs: ['helper:format-time', 'helper:travis-mb']
 }
 
 test 'it renders', ->