The city of San Diego’s expanding ranks of middle managers have become the go-to attack line on how spending got out of hand. But for years, city leaders saw them as the only way to get flexibility or roll out special projects. Now, everyone agrees there should be fewer of them. Mayor Todd Gloria historically supported these roles, but they cost the city’s general fund more than $49 million this fiscal year. Amid a projected $118 million budget deficit, he is now proposing cuts.