* On Ubuntu precise we now use the ondrej/php5-oldstable ppa. This can be
   manually enabled with by setting `$php::repo::ubuntu::oldstable` to
   `true`.
 * `$php::ensure` now defaults to `present` instead of `latest`. Though,
   strictly speaking, this represents a functional change, we consider this
   to be a bugfix because automatic updates should be enabled explicitely.
 * `$php::ensure` is not anymore passed to `php::extension` resources as
   default ensure parameter because this doesn't make sense.