freeze activesupport for a while

activesupport 4.0.0 has been released few days ago. 4.0.0 satisfy to bluepill-0.0.51 requirements(>=3.0.0) but require ruby 1.9. We have ruby 1.8 and not seemed like we want to use ruby 1.9.

Eugene Shurmin, from our team going to make a proposal how to avoid such troubles in future using ruby bundle, but for now the build is broken.