It was this same July week in 1981 that the inimitable Roger Doucet died at the age of 62, which is as good a reason as any to uplift yourself with three minutes of his anthem-singing artistry and screen “The Performer,” Norma Bailey’s 1978 National Film Board ode to the voice that filled the Montreal Forum in the 1970s and echoes still in Hab-loving hearts no matter where they might be.