FRANKFURT (Reuters) - European Central Bank President Mario Draghi defended his ultra-easy monetary policy stance on Thursday as his eight-year tenure at the bank closes in exactly the same place he started: trying to prop up a perpetually ailing currency bloc.With growth barely holding in positive territory and the outlook darkening, it was hardly the grand finale hoped for by Draghi, whose 2012 promise to do "whatever it takes" to save the euro -- code for rescuing heavily indebted countries..