Remove unnecessary petition load
Remove unnecessary petition load

The before_action `retrieve_petition` already loads the petition.

joelanman/e-petitions,StatesOfJersey/e-petitions,oskarpearson/e-petitions,alphagov/e-petitions,oskarpearson/e-petitions,unboxed/e-petitions,alphagov/e-petitions,StatesOfJersey/e-petitions,alphagov/e-petitions,joelanman/e-petitions,StatesOfJersey/e-petitions,unboxed/e-petitions,joelanman/e-petitions,oskarpearson/e-petitions,unboxed/e-petitions,alphagov/e-petitions,StatesOfJersey/e-petitions,unboxed/e-petitions