Remove simplecov

simplecov 0.9 dropped ruby 1.8 support, and stdlib is one of the oddball
modules that uses it. So we could probably just remove it and be okay.

(cherry picked from commit a7c129b22d)

spec/spec_helper.rb

@@ -9,7 +9,6 @@ end
 
 require 'puppet'
 require 'rspec-puppet'
-require 'simplecov'
 require 'puppetlabs_spec_helper/module_spec_helper'
 require 'puppet_spec/verbose'
 require 'puppet_spec/files'
@@ -21,10 +20,6 @@ require 'monkey_patches/alias_should_to_must'
 require 'mocha/setup'
 
 
-SimpleCov.start do
-  add_filter "/spec/"
-end
-
 
 RSpec.configure do |config|
   config.before :each do