Sections 111 to 116 of this title are repealed on the one hundred and eightieth day after August 9, 1939: Provided, however, That the notices with respect to imported alfalfa and red clover seed promulgated by the Secretary of Agriculture under the authority of sections 111 to 116 of this title, and in effect on August 9, 1939, shall remain with the same full force and effect as if promulgated under this chapter