Spurious warnings from old CMake projects

From lhcb/Rec!2657 (comment 5094665)

Panoptes: Download contains additinal ref files we didn't expect: {'Rich/Panoptes/tests/refs/rich_ref_index_calib.ref',
 'Rich/Panoptes/tests/refs/rich_ref_index_calib.ref.x86_64_v3-opt',
 'Rich/Panoptes/tests/refs/rich_ref_index_calib_prkalmanfilter.ref',
 'Rich/Panoptes/tests/refs/rich_ref_index_calib_prkalmanfilter.ref.x86_64_v3-opt'}
Panoptes: Download is missing ref files we expected: {'/workspace/build/Panoptes/Rich/Panoptes/tests/refs/rich_ref_index_calib.ref',
 '/workspace/build/Panoptes/Rich/Panoptes/tests/refs/rich_ref_index_calib.ref.x86_64_v3-opt',
 '/workspace/build/Panoptes/Rich/Panoptes/tests/refs/rich_ref_index_calib_prkalmanfilter.ref',
 '/workspace/build/Panoptes/Rich/Panoptes/tests/refs/rich_ref_index_calib_prkalmanfilter.ref.x86_64_v3-opt'}

The actual reference update seems to make sense