Remove Haml helpers from the visibility level spec.

spec/helpers/visibility_level_helper_spec.rb

 require 'spec_helper'
 describe VisibilityLevelHelper do
-  include Haml::Helpers
-
-  before :all do
-    init_haml_helpers
-  end
   let(:project)          { build(:project) }
   let(:group)            { build(:group) }