Lockdown Chef version; workaround ohai regression

ohai recently started reporting root as the current user instead of the SUDO_USER, I think this was due to this commit: https://github.com/opscode/ohai/commit/fec9467a0c93b203e97447207352745536c2b471

This change breaks a bunch of recipes in sprout so we need a temporary solution until we figure out the right thing to do in response to the ohai change.