Enables RSpec/EmptyLineAfterFinalLet cop & fixes all issues

Read about cop at http://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/EmptyLineAfterFinalLet

spec/features/legislation/draft_versions_spec.rb

@@ -140,6 +140,7 @@ feature 'Legislation Draft Versions' do
 
   context 'Annotations', :js do
     let(:user) { create(:user) }
+
     background { login_as user }
 
     scenario 'Visit as anonymous' do
@@ -218,6 +219,7 @@ feature 'Legislation Draft Versions' do
   context "Merged annotations", :js do
 
     let(:user) { create(:user) }
+
     background { login_as user }
 
     scenario 'View annotations and comments in an included range' do

spec/features/legislation/processes_spec.rb

@@ -3,6 +3,7 @@ require 'rails_helper'
 feature 'Legislation' do
 
   let!(:administrator) { create(:administrator).user }
+
   shared_examples "not published permissions" do |path|
 
     let(:not_published_process) { create(:legislation_process, :not_published, title: "Process not published") }