LONDON (Reuters) - Euro zone bond markets were braced on Thursday for the European Central Bank to announce fresh stimulus measures, but uncertainty reigned over the bank's precise moves.Government bond yields in the bloc, a touch lower in morning trade, have risen from record lows reached just a week ago on growing doubts that the ECB will begin a fresh round of asset purchases, known as quantitative easing (QE). A cut in the ECB's minus 0.4% deposit rate - which would be the first since 2016 -..