Handle shorthand actions

[ssutar]

The transform errors out if we have actions like

import someActionUtil from 'some/action/util';

const Foo = Component.extend({
  actions: {
     someActionUtil
  }
});

It should be handled correctly

import someActionUtil from 'some/action/util';

const Foo = Component.extend({
   @action
   someActionUtil;
});