vchoi_fork

[svn-r9457] Purpose:
Bug fix.

Description:
The previous H5_ULLONG_TO_FP_CAST_WORKS fix does not quite work
since the problem was an error during compiling while the fix
was trying to check for the error condition during runtime.
The MS-Compiler still complains about not supporting ULLONG
to Float.

Solution:
A temperary patch is to have two #define of H5Z_XFORM_TYPE_OP
according to if H5_ULLONG_TO_FP_CAST_WORKS is defined.  This
works but a better solution is needed.

Platforms tested:
Windows (by Kent) and heping (Linux by me).