GLOBAL MARKETS-Draghi drives euro to 4-1/2 year low

(Updates after European markets open, changes dateline from previous SYDNEY)* ECB chief says ready to act on low inflation* Euro touches lowest since June 2010 before steadying* European shares fall, euro zone periphery government debt gains* Oil mixed, Asia stock markets mostly firmerBy Patrick GrahamLONDON, Jan 2 (Reuters) - The euro took another downward lurch on Friday, sinking to a 4-1/2 year