By Rodrigo Viga Gaier RIO DE JANEIRO (Reuters) -Brazil’s main presidential candidates traded accusations of corruption in their last debate before Sunday’s election, with little discussion of proposals to govern the South American country. Incumbent far-right President Jair Bolsonaro called his leftist rival, former president Luiz Inacio Lula da Silva, the boss of a criminal gang that ran a “kleptocracy” during his two-term presidency from 2003 to 2010. Lula, who has a comfortable double-digit lead going into the first round of voting, called Bolsonaro a “shameless” liar whose government had c…