Fix Rubocop offenses

Gemfile

@@ -2,39 +2,39 @@ source ENV['GEM_SOURCE'] || "https://rubygems.org"
 
 group :test do
   puppetversion = ENV.key?('PUPPET_VERSION') ? "= #{ENV['PUPPET_VERSION']}" : ['>= 4.9']
-  gem "rake"
+  gem "metadata-json-lint"
   gem "puppet", puppetversion
+  gem "puppetlabs_spec_helper"
+  gem "rake"
   gem "rspec", '> 3.4.0'
   gem "rspec-puppet"
-  gem "puppetlabs_spec_helper"
-  gem "metadata-json-lint"
   gem "rspec-puppet-facts"
-  gem 'rubocop', '0.42.0'
+  gem 'rubocop'
   gem 'simplecov', '>= 0.11.0'
   gem 'simplecov-console'
 
   gem "puppet-lint-absolute_classname-check"
-  gem "puppet-lint-leading_zero-check"
-  gem "puppet-lint-trailing_comma-check"
-  gem "puppet-lint-version_comparison-check"
   gem "puppet-lint-classes_and_types_beginning_with_digits-check"
-  gem "puppet-lint-unquoted_string-check"
+  gem "puppet-lint-leading_zero-check"
   gem 'puppet-lint-resource_reference_syntax'
+  gem "puppet-lint-trailing_comma-check"
+  gem "puppet-lint-unquoted_string-check"
+  gem "puppet-lint-version_comparison-check"
 
   gem 'json_pure', '<= 2.0.1' if RUBY_VERSION < '2.0.0'
 end
 
 group :development do
-  gem "travis"              if RUBY_VERSION >= '2.1.0'
-  gem "travis-lint"         if RUBY_VERSION >= '2.1.0'
-  gem "puppet-blacksmith"
   gem "guard-rake" if RUBY_VERSION >= '2.2.5' # per dependency https://rubygems.org/gems/ruby_dep
-  gem 'yard'
+  gem "puppet-blacksmith"
   gem 'puppet-strings'
+  gem "travis" if RUBY_VERSION >= '2.1.0'
+  gem "travis-lint" if RUBY_VERSION >= '2.1.0'
+  gem 'yard'
 end
 
 group :system_tests do
   gem "beaker"
-  gem "beaker-rspec"
   gem "beaker-puppet_install_helper"
+  gem "beaker-rspec"
 end