vchoi_fork

[svn-r11292] Purpose:
"bug fix"

Description:
The test_mpio_derived_dtype() often hangs when fails.  So it was
not run by default to avoid hanging the daily tests or confusing
users.  But then new system or new codes in collective chunk fails
while one can't tell for sure if it is because of the complicated
derived type failures or something else.

Solution:
Changed the logic so it is skipped only if it is known that
the complicated MPI derived type does not work.  (This is
indicated by macro H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS NOT
defined.

Platforms tested:
heping pp (where it is tested by default).
Modi4 pp (where it is SKIPPED by default.)
I also forced modi4 to test it and modi4 said it actually
is working and should change the setting of
H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS to working?!!

Misc. update: