[Twisted-Python] Dud bug tracker link on tm.com

From anywhere other than the front page (e.g. the uber-nifty success stories page, http://twistedmatrix.com/services/success), the "Bug Tracker" link points to: http://twistedmatrix.com/http://sourceforge.net/tracker/?func=browse&group_id=49387&atid=456015

-Andrew.