Add hash_index support

This is added in https://bitbucket.org/pypa/bandersnatch/pull-requests/16/add-option-to-dir-hash-index-files/diff

Change-Id: I29278264af04f1bce4388a2bd58f0334807bb6e1

manifests/mirror.pp

@@ -22,6 +22,7 @@ class bandersnatch::mirror (
   $static_root = '/srv/static',
   $user = 'root',
   $group = 'root',
+  $hash_index = false,
 ) {
 
   if ! defined(File[$static_root]) {

templates/bandersnatch.conf.erb

@@ -20,6 +20,10 @@ timeout = 10
 ; - anything beyond 50 is probably unreasonable and avoided by bandersnatch
 workers = 3
 
+<% if @hash_index == true -%>
+hash-index = true
+<% end -%>
+
 ; Whether to stop a sync quickly after an error is found or whether to continue
 ; syncing but not marking the sync as successful. Value should be "true" or
 ; "false".