JavaScript 1.7's let expressions are deprecated https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let#Non-standard_let_extensions
Bug 1116632 remove unnecessary blocks as a result of d679c102c52d4ec6d6cc07541675138560c349f9
Bug 1116632 removing let blocks from the tests
Merge pull request #1786 from erikvold/1116632

Bug 1116632 - Removing let blocks r=erikvold
Merge branch 'master' of https://github.com/mozilla/addon-sdk
using sudo: false for faster travis builds

see: http://blog.travis-ci.com/2014-12-17-faster-builds-with-container-based-infrastructure/