Fix deprecation warnings in inline templates

The puppet-swift modules emit deprecation warnings of the form:

Warning: Variable access via 'pipeline' is deprecated. Use
  '@pipeline' instead. template[inline]:2
   (at (erb):2:in `result')

These are due to missing @ signs in inline ERB templates in
storage/server.pp and proxy.pp.  This patch fixes them.

Change-Id: I3745cfd86c4332f00bc10a0999088691b3833147
Closes-Bug: #1282717

manifests/proxy.pp

@@ -95,7 +95,7 @@ class swift::proxy(
   $required_classes = split(
     inline_template(
       "<%=
-          (pipeline - ['proxy-server']).collect do |x|
+          (@pipeline - ['proxy-server']).collect do |x|
             'swift::proxy::' + x.gsub(/-/){ %q(_) }
           end.join(',')
       %>"), ',')

manifests/storage/server.pp

@@ -63,7 +63,7 @@ define swift::storage::server(
   $required_middlewares = split(
     inline_template(
       "<%=
-        (pipeline - ['${type}-server']).collect do |x|
+        (@pipeline - ['${type}-server']).collect do |x|
           'Swift::Storage::Filter::' + x.capitalize + '[${type}]'
         end.join(',')
       %>"), ',')