Notwithstanding the provisions of § 36-19, no authority established in the City of Portsmouth shall make any cooperation agreement with the governing body of the city for any public housing project that is not authorized or approved by the governing body of the city on or before July 1, 1960, unless a cooperation agreement for such public housing project has been approved by a majority of the qualified voters of the city voting in an election called by the governing body of the city for such purpose. The procedure for such election shall conform to general law. The provisions of this section shall not affect or impair the provisions of § 36-19.1, nor shall they apply to such low rent public housing units determined by the governing body of the city as necessary for the satisfactory relocation of families to be displaced by the city’s urban renewal program.