The National Film Board of Canada turns 75 today, which is as good a reason as any to screen “The Performer,” Norma Bailey’s 1978 ode to the inimitable Roger Doucet, whose voice filled Hab-loving hearts and the Montreal Forum in the 1970s. (Other than P.K. Subban, of course. Subban might be a better reason.) For more on the NFB and the hockey in its heritage, this way.