Bug#1053267: hickle: test_H5NodeFilterProxy fails with h5py 3.9.0: Unable to delete attribute (no write intent on file)

[Drew Parsons]

reopen 1053267
thanks

hickle 5.0.2-6 was intended to fix the "No write intent on file" error 
in Bug#1053267.

But the error still occurs,
see 
https://ci.debian.net/data/autopkgtest/testing/amd64/h/hickle/38426042/log.gz

Note that this time the error occurred with old h5py 3.7.0, so there 
must be more to the problem than just h5py 3.9.0 on its own.