Add Gemfile and puppet 4 checks

In anticipation of puppet 4, start trying to deal with puppet 4 things
that can be helpfully predicted by puppet lint plugins.

Change-Id: Id207ce3993e991f8bc38e68d67e009e522d6ace3

.gitignore

@@ -0,0 +1,2 @@
+Gemfile.lock
+.bundled_gems/

Gemfile

@@ -0,0 +1,35 @@
+source 'https://rubygems.org'
+
+group :development, :test do
+  gem 'puppetlabs_spec_helper', :require => false
+
+  gem 'metadata-json-lint'
+  # This is nice and all, but let's not worry about it until we've actually
+  # got puppet 4.x sorted
+  # gem 'puppet-lint-param-docs'
+  gem 'puppet-lint-absolute_classname-check'
+  gem 'puppet-lint-absolute_template_path'
+  gem 'puppet-lint-trailing_newline-check'
+
+  # Puppet 4.x related lint checks
+  gem 'puppet-lint-unquoted_string-check'
+  # Empty string changed to mean "true" in puppet 4. While it's ok to
+  # assign the empty string to a variable, if that variable is checked
+  # with if $variable instead of if $variable == '', it'll be an opposite
+  # behavior. However, the check is too violated by us to use right now.
+  gem 'puppet-lint-empty_string-check'
+  gem 'puppet-lint-leading_zero-check'
+  gem 'puppet-lint-variable_contains_upcase'
+  gem 'puppet-lint-numericvariable'
+  gem 'puppet-lint-spaceship_operator_without_tag-check'
+  gem 'puppet-lint-undef_in_function-check'
+
+  if puppetversion = ENV['PUPPET_GEM_VERSION']
+    gem 'puppet', puppetversion, :require => false
+  else
+    gem 'puppet', '~> 3.0', :require => false
+  end
+
+end
+
+# vim:ft=ruby

manifests/init.pp

@@ -46,7 +46,7 @@ class puppet (
       $pin_puppetdb = '2.'
     }
     default: {
-      fail('Puppet version not supported')
+      fail("Puppet version ${pin_puppet} not supported")
     }
   }