Fix header and footer caching
Fix header and footer caching

Due to erroneous information from @pixeltrix the `:home_page` key was
removed from the `:header` fragment and not the `:footer` fragment as
it should've been.

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