Chefboyardee, the Omaha, NE.-based unit of food giant ConAgra Foods (NYSE: CAG), reached out to Second City to come up with a humorous social media-based campaign to reintroduce the pop top can lids that Chefboyardee had — it turns out — unwisely decided to phase out in the spring of 2013. After backlash from fans of the pop top lids, Chefboyardee decided to reinstate the pop tops earlier this spring. Now Second City is using the return of the lids to poke fun at all those fringe groups who…