(Reuters) – Slovak opposition failed to fire powerful Finance Minister Igor Matovic on Tuesday, but the result spells further instability for the firmly pro-Western and pro-Ukraine government. The row over Matovic, a divisive former prime minister and founder of the main ruling party OLANO, pushed the liberal SaS party to quit the centre-right government last month, which cost the Cabinet its parliamentary majority. However, even with SaS on board, only 73 lawmakers backed the motion to dismiss Matovic, three votes short of the required absolute majority in the 150-seat parliament. SaS, which …