Fix AmpGen CMake config to include TBB
Fix for AmpGen's CMake configuration to include TBB to fix linking problem for slc6-gcc62
in master (v52r0 built against Gaudi v29r0 and LHCb v43r1).
Fix for AmpGen's CMake configuration to include TBB to fix linking problem for slc6-gcc62
in master (v52r0 built against Gaudi v29r0 and LHCb v43r1).