BAGHDAD Iraqi leaders trying to complete a new constitution moved toward deals on such contentious issues as Shiite autonomy, sharing oil revenues and Kurdish self-rule. But as they progressed on those fronts, a tentative agreement that would have given Islam an expanded role in the state and in family disputes appeared to unravel.Islam is back on the table, said a person close to the negotiations, who spoke on the condition of anonymity, citing the sensitivity of the talks.