Work around HDF5-bug in FindCasacore.cmake
FindCasacore.cmake clobbers HDF5_LIBRARIES, because it searches for HDF5 without specifying "COMPONENTS CXX". Unfortunately, there is no easy fix to FindCasacore.cmake, because it uses a macro to do some internal find_package() commands, and this macro only does very basic argument parsing.
The work-around is to call "find_package(Casacore)" before calling "find_package(HDF5 ...)" in the top-level CMakeLists.txt file. It works, but doesn't solve the real issue.