Fixed an issue that could occur when using temporary IDs with newly created records. Because the `id` property is a computed property, once it has been read (i.e. `myNewRecord.get('id')`), it will remain cached for any further reads. This can become an issue in situations where the ID of the record changes after being saved to the server. For instance, a new record may be given a temporary ID when it is created and the temporary id may be accessed via `get`. After that record is saved to the server, a call to `store.dataSourceDidComplete(RecordType, newBody, newBody.id)` would properly update the `id` value in the store, but would fail to clear the record instance's cache of `id`. Therefore, a successive call to `get('id')` would return the old value.
White space tidies.