spec: pin rspec-puppet to 1.0.1

rspec-puppet (2.0.0) was released yesterday[1], this new version broke
puppet-openstack unit tests (undefined method `resource')[2] as talked on
and in a second time to update your specs to 2.0.0 and rspec 3.x`)

[1] rodjek/rspec-puppet@8459e14
[2] http://logs.openstack.org/45/105245/6/check/gate-puppet-nova-puppet-unit-3.3/3682541/console.html

Change-Id: Ia41394433be65435fc7de6327a5659b26e1a85a5
Partial-bug: #1417604
(cherry picked from commit 71f27f1)

Gemfile

@@ -3,6 +3,7 @@ source 'https://rubygems.org'
 group :development, :test do
   gem 'puppetlabs_spec_helper', :require => false
   gem 'puppet-lint', '~> 0.3.2'
+  gem 'rspec-puppet', '~> 1.0.1'
   gem 'metadata-json-lint'
   gem 'puppet-syntax'
   gem 'rake', '10.1.1'