Figure out why `unloadAll()` is needed to refresh google drive permission data after a failed delete and find away to eliminate that need if possible.

[begedin]

Moved from venkatd/storypad

As mentioned in venkatd/storypad#142, there seems to be some sort of caching going on in ember-data which prevents google drive permissions from getting properly refreshed from the drive API on a failed delete action.

Because of that, the following steps are required to refresh with the correct data:

record.rollback();
store.unloadAll('google-drive-permission');
store.find('google-drive-permission');

Since unloadAll() is marked as private in the Ember documentation, it should probably not be used here, so there must be another, more proper way to do it.

[begedin]

This looks to be a related issue:

emberjs/data#1632