[Cmake] HDF5_INCLUDE_DIR -> HDF5_INCLUDE_DIRS
[Cmake] HDF5_INCLUDE_DIR -> HDF5_INCLUDE_DIRS

The former is deprecated for quite some time.
https://cmake.org/cmake/help/v3.5/module/FindHDF5.html

Kind of broke for me during the tübingenhackathon and the d fixed it

stoewer/nix