Fix a bug in seen_media for sub folder case, a=chris

diff --git a/src/controllers/components/SocialComponent.php b/src/controllers/components/SocialComponent.php
index 3bd9ec7ed..b7fb43aa4 100644
--- a/src/controllers/components/SocialComponent.php
+++ b/src/controllers/components/SocialComponent.php
@@ -3564,7 +3564,7 @@ EOD;
         $parent = $this->parent;
         $group_model = $parent->model("group");
         $media_name = $parent->clean($_REQUEST['n'], "string");
-        $hash_id = L\crawlHash($page_id . $media_name, $sub_path);
+        $hash_id = L\crawlHash($page_id . $media_name . $sub_path);
             if (!empty($_SESSION['USER_ID']) && $_SESSION['USER_ID'] !=
                 C\PUBLIC_USER_ID) {
             if (empty($_SESSION['seen_media'])) {