Source map temp fixes

Some housekeeping to release beta 14.1. We need beta14.1 as due to the `<%= versionStamp %>` (which was fixed recently by @tricknotes in https://github.com/emberjs/data/pull/2631) and also to note the dropped compatibility for Ember <= 1.7.1(http://emberjs.com/blog/2014/11/24/ember-data-1-0-beta-12-released.html)