Fixing "urls" within TagsTableTag->bind()

The "urls" are stored within $array['urls'], not within $item->urls ($item doesn't even exist in this context).
Thanks piotr_cz to notify in https://groups.google.com/d/msg/joomla-dev-cms/R8x3PcaL7nI/3N0I4_5KHCcJ

Tracker: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=30595