Chicago’s Lyric Opera is tightening its belt a bit this season, and is going to extraordinary lengths to keep its subscribers and donors happy. Part of that effort can be seen in the company’s choice of programs for next season: plenty of old warhorses, not a single American opera in the bunch, and a new staging of “Rigoletto” to replace the last new staging of “Rigoletto” Lyric mounted in 2000, which prompted dozens of furious letters from subscribers due to its, um, “frank sexuality.”