Update rspec-rails and rspec-core
Update rspec-rails and rspec-core

Fixes deprecation warnings for last_comment.

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