disable MCTester_i until we are sure we can remove it from release. Add Rivet_i back to Athena
disable MCTester_i until we are sure we can remove it from release. Add Rivet_i back to Athena. MCTester is most probably no longer used, so we remove it from the release. It should also solve the remaining problems of LCG_100_ATLAS_2 SPI-1889.