hdf5_msb

[svn-r12343] Purpose:
Bug fix for collective chunk IO

Description:
Several options have been provided inside HDF5 library for
obtaining chunk addresses when doing collective chunk IO.
One option is to obtain chunk addresses for one process and broadcast
to other processes. This option needs all processes to participate.
If using link-chunked IO without any optimizations,
sometimes this is not true due to the random initialization for one variable at mpich 1.2.7.
This is a bug inside the collective chunk IO code.


Solution:
1.Initalize all the variables to some safe numbers,
2. Avoid using MPI broadcast to obtain the chunk address if possible
   until more performance studies have been done.
3. Seems okay to obtain chunk addresses individually for each processor.
This option may cover most cases.




Platforms tested:
h5committest(copper is not usable)
NCSA teragrid (mpich 1.2.5)
mir 64-bit linux (mpich 1.2.6)

Misc. update: