vchoi_fork

[svn-r11866] Purpose:
bug fix 504

Description:
testpar/t_mpi would hang if  $HDF5_NOCLEANUP is set.  E.g.,
% env HDF5_NOCLEANUP=yes mpirun -np 3 ./t_mpi

This happened because the environment variables are not exported to all
mpi processes by the mpirun command.  So, some attempted to do cleanup
while others don't and some hang waiting for others to act.

Solution:
Instead individual program checking getenv, they all just called h5_cleanup
no matter.  h5_cleanup now uses getenv_all to check the $HDF5_NOCLEANUP if
it is in parallel mode.

Platforms tested:
h5committested, tested pp in heping too.