HDF5 file descriptor remains after closed

[tomyun]

It is suspicious that HDF5 files are not properly closed when GDALClose() is called. A snippet below may reproduce the issue.

from osgeo import gdal
ds = gdal.Open('test.h5')
# at this point, `lsof | grep test.h5` should show an open descriptor.
ds = None
# at this point, `lsof | grep test.h5` should show nothing, but it persists.

Same test with other formats like tiff worked flawlessly. It doesn't look like Python-only, as multiple gdal_translate calls from a process still showed a bunch of open descriptors, even after each command had been terminated.

It might be relevant to the delayed close described in HDF5 API, though I have no clue to address it. ​http://www.hdfgroup.org/HDF5/doc/RM/RM_H5F.html#File-Close

[Even Rouault]

Fixed in trunk (r26061) and branches/1.10 (r26062)