Fix compilation with clang11

Fixes errors of this type:

../Detector/Rich2/src/Rich2GeoUtil.cpp:102:75: error: cannot pass object of non-trivial type 'const std::string' (aka 'const basic_string<char>') through variadic function; call will abort at runtime [-Wnon-pod-varargs]
            "Rich2GeoUtil : ", "Now building Rich2SuperStrTransforms %s", aSupStrPhysFileName );

Some warnings still remain.