Remove no-longer-used experiment code

Author: ragesoss

app/presenters/experiments_presenter.rb

@@ -1,13 +1,11 @@
 # frozen_string_literal: true
 
-require_dependency "#{Rails.root}/lib/experiments/spring2018_cmu_experiment"
-
 class ExperimentsPresenter
   def initialize(course)
     @course = course
   end
 
-  ACTIVE_EXPERIMENTS = [Spring2018CmuExperiment].freeze
+  ACTIVE_EXPERIMENTS = [].freeze
   def experiment
     @experiment ||= ACTIVE_EXPERIMENTS.find do |exp|
       @course.flags[exp::STATUS_KEY] == 'email_sent'

app/views/courses/course.json.jbuilder

@@ -84,9 +84,4 @@ json.course do
     json.passcode @course.passcode.blank? ? '' : '****'
     json.canUploadSyllabus false
   end
-
-  if user_role == CoursesUsers::Roles::INSTRUCTOR_ROLE
-    exeriment_presenter = ExperimentsPresenter.new(@course)
-    json.experiment_notification exeriment_presenter.notification if exeriment_presenter.experiment
-  end
 end