Address ordering issue with HTTP VFD, H5FDunregister

[WardF]

• Fixes nc_create_par triggers HDF5 error stack message related to H5FDunregister #2990

Based on the feedback on from @jhendersonHDF, I was able to eliminate in the error stack messages related to H5FDunregister, in my own environment (Ubuntu 22.04). I am testing this in other environments/compiler combinations, and I will integrate the PR @edwardhartnett put up to integrate a test for this issue, #3012, before final merge.

[WardF]

This fixed the issue with HDF-DIAG messages being printed, but I am still seeing test failures in nc_test4/run_par_tests.sh on Ubuntu 24.04 using mpich and a self-built libhdf5 1.14.4, using LDFLAGS=-"Wl,-Bsymbolic-functions -flto=auto -Wl,-z,relro"

*** Testing more advanced parallel access.
*** Testing parallel IO for raw-data with MPI-IO (driver)...ok.
*** Testing parallel IO for different hyperslab selections with MPI-IO (driver)...ok.
*** Testing parallel IO for extending variables with MPI-IO (driver)...ok.
*** Testing parallel IO for raw-data with MPIPOSIX-IO (driver)...
*** Testing more advanced parallel access.
*** Testing parallel IO for raw-data with MPI-IO (driver)...
*** Testing more advanced parallel access.
*** Testing parallel IO for raw-data with MPI-IO (driver)...
*** Testing more advanced parallel access.
*** Testing parallel IO for raw-data with MPI-IO (driver)...
*** Testing more advanced parallel access.
*** Testing parallel IO for raw-data with MPI-IO (driver)...
*** Testing more advanced parallel access.
*** Testing parallel IO for raw-data with MPI-IO (driver)...Sorry! Unexpected result, /home/vagrant/Desktop/netcdf-c/nc_test4/tst_parallel3.c, line: 284
Sorry! Unexpected result, /home/vagrant/Desktop/netcdf-c/nc_test4/tst_parallel3.c, line: 120

*** Testing more advanced parallel access.
*** Testing parallel IO for raw-data with MPI-IO (driver)...
*** Testing more advanced parallel access.
*** Testing parallel IO for raw-data with MPI-IO (driver)...Sorry! Unexpected result, /home/vagrant/Desktop/netcdf-c/nc_test4/tst_parallel3.c, line: 284
Sorry! Unexpected result, /home/vagrant/Desktop/netcdf-c/nc_test4/tst_parallel3.c, line: 91

[WardF]

This also fails using the Ubuntu-provided libhdf5-mpich-dev package.