SALEM — Gov. John Kitzhaber will propose an increase in funding for Oregon schools, but the money wouldn’t be enough to reduce class sizes unless the Legislature cuts pension benefits for retired teachers and other public employees, his staff said Thursday. The governor’s budget proposal, scheduled for release today, will include $6.15 billion in K-12 school funding over the next two years, according to a summary released by his office. That’s an 8-percent increase over current funding, but not enough to cover the $6.3 billion it would cost to maintain the current level of service in schools. Kitzhaber hopes his …