Separate system and unit test gems

This commit brings the .travis.yml and Gemfile files more in line with
the other modules. This should fix the broken TravisCI builds.

.travis.yml

@@ -1,6 +1,6 @@
 ---
 language: ruby
-bundler_args: --without development
+bundler_args: --without system_tests
 script: "bundle exec rake validate && bundle exec rake lint && bundle exec rake spec SPEC_OPTS='--format documentation'"
 matrix:
   fast_finish: true

Gemfile

@@ -1,14 +1,18 @@
-source 'https://rubygems.org'
+source ENV['GEM_SOURCE'] || "https://rubygems.org"
 
-group :development, :test do
-  gem 'rake', '10.1.1',          :require => false
-  gem 'rspec-puppet', '>=1.0.0', :require => false
+group :development, :unit_tests do
+  gem 'rake',                    :require => false
+  gem 'rspec-puppet',            :require => false
   gem 'puppetlabs_spec_helper',  :require => false
   gem 'puppet-lint',             :require => false
-  gem 'serverspec',              :require => false
-  gem 'beaker',                  :require => false
-  gem 'beaker-rspec',            :require => false
-  gem 'pry',                     :require => false
+  gem 'simplecov',               :require => false
+  gem 'puppet_facts',            :require => false
+  gem 'json',                    :require => false
+end
+
+group :system_tests do
+  gem 'beaker-rspec',  :require => false
+  gem 'serverspec',    :require => false
 end
 
 if facterversion = ENV['FACTER_GEM_VERSION']