Fix for: BHV-9729

Originally found by @DavidUM with a proposed fix https://github.com/enyojs/enyo/pull/751, this is the same fix with minimal changes to the existing code and a similar normalization in the `modelsRemoved()` method.

Enyo-DCO-1.1-Signed-Off-By: Cole Davis (cole.davis@lge.com)