Photo: Rowland Scherman/Getty Image; Searchlight Pictures In its retelling of Bob Dylan’s rise through the Greenwich Village folk scene and eventual decision to go electric at the Newport Folk Festival, A Complete Unknown is unafraid to indulge in a few flights of fancy — scenes that blatantly didn’t occur as written, but that nonetheless consolidate some larger idea about Dylan. In one of the more egregious instances, the Cuban Missile Crisis is happening, and panic strikes New York City,