Normalize Gemfile & pin tests to rspec < 2.99

Pin to rspec < 2.99 until rspec-puppet officially supports rspec 3.x.
This is to avoid warnings due to deprecated matchers in the
rspec-puppet gem.

This change is also intended to normalize the Gemfile for all stackforge
puppet modules.  This should facilitate pinning gem versions when
releasing new stable branches, since the same diff can be used for all
repos.

Change-Id: Id689c9b065f3a45088ca9518d3cd2f49d03d2c38
Partial-Bug: #1326034

Gemfile

@@ -4,6 +4,9 @@ group :development, :test do
   gem 'puppetlabs_spec_helper', :require => false
   gem 'puppet-lint', '~> 0.3.2'
   gem 'rake', '10.1.1'
+  gem 'rspec', '< 2.99'
+  gem 'json'
+  gem 'webmock'
 end
 
 if puppetversion = ENV['PUPPET_GEM_VERSION']