Notwithstanding any other provision of law, the State Department of Parks and Recreation shall extend until December 31, 1979 the existing concession agreement, dated May 6, 1948, as amended March 21, 1958, between the State of California and the Girl Scout Council of San Diego County, Incorporated, relating to the “Stonewall Group Organizational Area” and premises in Cuyamaca Rancho State Park, San Diego County, California. Thereafter, there shall be no such agreement in force or effect other than an agreement consummated pursuant to Article 1.5 (commencing with Section 5019.10) of this chapter.