Gerard Butler’s long-awaited “Greenland” sequel is finally set to go into production in April, Variety can confirm. The disaster film, titled “Greenland: Migration,” will see Butler reunite with director Ric Roman Waugh and “Greenland” writer Chris Sparling. “Deadpool” star Morena Baccarin will also return for the sequel. Sparling has co-written “Greenland: Migration” alongside Mitchell Lafortune. […]