Fix format arguments to match the data types

[mr-c]

No description provided.

[Bisaloo]

I'm not sure this is right. The docs state:

HDF5 defines a data type called hsize_t which is used for sizes of datasets and is, by default, defined as unsigned long long.

http://docs.hdfgroup.org/archive/support/HDF5/doc/TechNotes/BigDataSmMach.html

And it is indeed unsigned long long for me.

This is also what we are seeing in CI.

It seems the proposed fix is very specific to your setup. Or am I missing something?