The new broom swept unusually clean at Paramount Pictures over the last year or so. Gone are high executives like Sherry Lansing and Jonathan Dolgen, studio fixtures like the superstar Tom Cruise and the producer Scott Rudin, and legions of underlings, all cleared out as a new chief, the former talent manager and producer Brad Grey, took charge. But one thing remains somehow unchanged on the company’s Hollywood lot. Across a bright green lawn from the executive office building, under a familiar brown awning that would be at home on Park Avenue, the production company named for its owner, Robert Evans, still holds sway. Ross Johnson reports.