hdf5_ep

[svn-r6617] Purpose:
Bug fix.

Description:
The macro MAX defined here is very commonly defined, e.g., AIX systems.
The compiler did not like duplicated macro defines.

Solution:
H5_MAX is already defined in H5f90.h and used in other code.
Remove MAX and change its use to H5_MAX.

Platforms tested:
"h5committested", plus tested at LLNL Blue.

Misc. update: