HDF5 tests are not run by the pipelines
This is a minor thing; I'm just mentioning it so we don't forget...
Although HDF5 is installed in one of the CI configurations, the relevant tests (test_serialization.py) are not executed. On my own machine, where the standard h5py package is available, they are run when I do "nosetests -vv". So I expect there is some problem with the automatic setup (e.g. in install_h5py.sh).