vchoi_fork

[svn-r5408] Purpose:
    Performance enhancement

Description:
    Doing an MPI_File_sync() just before a file is closed causing a large
    performance loss.

Solution:
    Add flag to MPI file driver to avoid performance the MPI_File_sync() when
    the flag is set before a call to H5F_flush().

Platforms tested:
    IRIX64 6.5 (modi4)