fix one build warning in `minall`

Request Type: bug, chore

How to reproduce: build with `grunt`, warning shows in `minall`

Component(s): scope

Impact: small

Complexity: small

This issue is related to:

**Detailed Description:**

There are several more issues like this, but I'm not sure if I know the right way to fix them.

**Other Comments:**

Used code from cironunes/angular.js, slightly modified (Firefox should be abbreviated Fx, exception variable should not be reassigned).