Revert "Changes active_support to v4 to fix out-of-date deps in gemnasium"
Revert "Changes active_support to v4 to fix out-of-date deps in gemnasium"

This reverts commit 9ac923dded17072c5ac60679927dab795d15969a due to
incompatibility with Rails 3 apps (until we implement a way to support
both versions).

e-travel/agnostic_backend,e-travel/agnostic_backend