vendor: add default version for json.php

Change-Id: Ibd79ec6b5c5ccebfad52a91f7f8e2393f065ab82
diff --git a/prebuilt/wallpapers/json.php b/prebuilt/wallpapers/json.php
index 1418c78..70eb6b3 100644
--- a/prebuilt/wallpapers/json.php
+++ b/prebuilt/wallpapers/json.php
@@ -12,6 +12,7 @@
 		}
 
 		if (is_dir($path.'/'.$file)) {
+			$output[$path.'/'.$file] = list_files($path.'/'.$file);
 		} else {
 			$output[] = array("filename"=>$file, "timestamp"=>filemtime($path.'/'.$file));
 		}