Add next and prev link to media display 2, a=chris

diff --git a/src/controllers/components/SocialComponent.php b/src/controllers/components/SocialComponent.php
index 622a29e66..88ecd3a2f 100644
--- a/src/controllers/components/SocialComponent.php
+++ b/src/controllers/components/SocialComponent.php
@@ -2182,6 +2182,9 @@ class SocialComponent extends Component implements CrawlConstants
         }
         $folder_prefix = ($is_static) ? $base_url : $base_url . "&";
         $folder_prefix .= "page_id=". $page_id;
+        if (!empty($data['SUB_PATH'])) {
+             $folder_prefix .= "&sf=" . $data['SUB_PATH'];
+        }
         $url_prefix = $folder_prefix . "&arg=media";
         $prev_name = ($i < $num_resources &&
             isset($resources[$i - 1]['name'])) ?