Make it so we don't install Postgresql-8.4 client packages anymore,

reintroducing a change that had to be pulled due to an upstream failure with
Build-essential 2.0.0. Due to the way they handled their deprecation warning, it
was causing us to mysteriously fail compiling our recipes. As a result, this
commit also includes a fix for that, whenever we start pulling in upstream
things like new Build-essential. For Chef repos that are still on
Build-essential 1.4.2, this does not change any of that behavior.