By Gram Slattery and Gabriel Stargardter RIO DE JANEIRO (Reuters) -Brazil’s Jair Bolsonaro and his leftist rival Luiz Inacio Lula da Silva on Monday buckled up for four more weeks of intense election campaigning after the president’s unexpectedly strong showing in the first round set up a tight Oct. 30 runoff vote. Lula, a two-term former president who was jailed on corruption convictions that were later overturned, won the most votes in Sunday’s presidential election, and for many analysts is still the favorite to win the race later this month. But Bolsonaro’s better-than-expected performance…