ENYO-643: Revert changes to sample

### Issue
To address ENYO-403, a small change was made to the sample as I had originally believed this to be a sample-only issue based on some of our inline documentation and some false positives when testing the sample. In fact, there were some deeper issues with the synchronization of our various selection states for the `enyo.DataRepeater` control.

### Fix
The issues with the various selection states has been addressed by https://github.com/enyojs/enyo/pull/957, and as a result we can revert the original update to the sample.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>