hdf5_ep

[svn-r8867] Purpose:
    Bug fix

Description:
    Fix error in chunked dataset I/O where data written out wasn't read
correctly from a chunked, extendible dataset after the dataset was extended.

    Also, fix parallel I/O tests to gather error results from all processes,
in order to detect errors that only occur on one process.

Solution:
    Bypass chunk cache for reads as well as writes, if parallel I/O driver is
used and file is opened for writing.

Platforms tested:
    FreeBSD 4.10 (sleipnir) w/parallel
    Too minor to require h5committest