By W. Zachary MalinowskiCENTRAL FALLS, R.I. -- James A. Diossa, the front-runner to become the city's next mayor, has asked the state Board of Elections to block Central Falls' plans to have just two polling places open for the Dec. 11 special mayoral election. Providence Journal photo JAMES DIOSSA Diossa, who captured 59 percent of the vote in the Nov.