ppa_options not getting correct default

While working on updating unit tests for apt::ppa, found that if
apt::params hasn't already been included elsewhere, the $options
parameter is not picking up the correct defaults. Updated the code to
set default options after apt::params is included.
It's generally assumed that the base class of a module should always be included before any defined resources can be used. Otherwise we would have this defaults snipped littering our modules.