Fix issue with urls ending in ‘/’ getting normalized wrong

Normalizing them this way ruins the url by cutting off a character too many and
making the url invalid.

src/SemanticScuttle/Service/Bookmark.php

@@ -1138,7 +1138,7 @@ class SemanticScuttle_Service_Bookmark extends SemanticScuttle_DbService
 
         // Delete final /
         if (substr($address, -1) == '/') {
-            $address = substr($address, 0, strlen($address)-2);
+            $address = substr($address, 0, -1);
         }
 
         return $address;