Correct the relationship when managing the pinned file for a plugin

The reason this wasn't working before was largely due to the `onlyif` statement
in the exec resource, wihch ends up requiring puppet to run twice to get the
pinned file to work properly

Fixes voxpupuli#380

manifests/plugin.pp

@@ -137,10 +137,12 @@
     exec { "create-pinnedfile-${name}" :
       command => "touch ${plugin_dir}/${name}.jpi.pinned",
       cwd     => $plugin_dir,
-      require => File[$plugin_dir],
+      require => [
+                File[$plugin_dir],
+                Archive::Download[$plugin],
+                ],
       path    => ['/usr/bin', '/usr/sbin', '/bin'],
       onlyif  => "test -f ${plugin_dir}/${name}.jpi -a ! -f ${plugin_dir}/${name}.jpi.pinned",
-      before  => Archive::Download[$plugin],
       user    => $username,
     }
 

spec/defines/jenkins_plugin_spec.rb

@@ -12,6 +12,13 @@
   it { should contain_group('jenkins') }
   it { should contain_user('jenkins').with('home' => '/var/lib/jenkins') }
 
+  context 'the pinned file resource' do
+    it do
+      should contain_exec("create-pinnedfile-#{title}")
+          .that_requires("Archive::Download[#{title}.hpi]")
+    end
+  end
+
   context 'with my plugin parent directory already defined' do
     let(:pre_condition) do
       [
@@ -22,7 +29,6 @@
     include_examples 'manages plugins dirs'
   end
 
-
   describe 'without version' do
     it do
       should contain_archive__download('myplug.hpi').with(
@@ -31,6 +37,7 @@
       )
     end
     it { should contain_file('/var/lib/jenkins/plugins/myplug.hpi')}
+
   end
 
   describe 'with version' do