TAREK AMARA TUNISIAN riot police turned water cannons on protesters outside the heavily barricaded parliament as they tried to quell the largest rally yet since demonstrations began this month over inequality and police abuses. Hundreds of protesters had marched from the Ettadhamen district of the capital where young people have clashed nightly with police for more than a week, and were joined by hundreds more near the parliament. Police blocked the march with barricades to prevent protesters approaching the parliament building where lawmakers were holding a tense debate on a controversial government reshuffle. "The government that only uses police to…