Drop Jenkins test integration

Gemfile

@@ -8,7 +8,6 @@ group :rubocop do
 end
 
 group :test do
-  gem 'ci_reporter_test_unit'
   gem 'mocha'
   gem 'public_suffix'
   gem 'rack-test'

Rakefile

@@ -1,4 +1,3 @@
-require 'ci/reporter/rake/test_unit'
 require 'rake'
 require 'rake/testtask'
 require 'rubocop/rake_task'
@@ -16,8 +15,3 @@ Rake::TestTask.new(:test) do |t|
   t.test_files = FileList['test/**/*_test.rb']
   t.verbose = true
 end
-
-namespace :jenkins do
-  desc nil # No description means it's not listed in rake -T
-  task :unit => ['ci:setup:testunit', :test]
-end