Refactor some RSpec Facter test helpers into spec_helper.rb

This fixes a minor test regression introduced in voxpupuli#111, wherein Facts defined in
some rspec-puppet were not getting flushed before running the RSpec unit tests

spec/spec_helper.rb

@@ -9,6 +9,20 @@
   # which is a totally piece of garbage mocking library
   c.mock_with :rspec
 
+  def clear_facts
+    Facter.clear
+    Facter.clear_messages
+  end
+
+  c.before(:each, :type => :fact) do
+    # Need to make sure we clear out our facts at the start to make sure that
+    # we don't pick up some facts left over from rspec-puppet
+    clear_facts
+  end
+  c.after(:each, :type => :fact) do
+    clear_facts
+  end
+
   c.before :each do
     if self.respond_to? :pre_condition
       if pre_condition.instance_of? Array

spec/unit/plugins_spec.rb

@@ -155,12 +155,6 @@
     Jenkins::Facts.add_facts
   end
 
-  after :each do
-    # Make sure we're clearing out Facter every time
-    Facter.clear
-    Facter.clear_messages
-  end
-
   context 'on Linux' do
     let(:kernel) { 'Linux' }