hdf5_ep

[svn-r5530] Purpose:
    Code Cleanup
Description:
    Removed some compiler warnings.
Solution:
    In a few cases, NULL was being returned when a FAIL was supposed to
    be returned instead. There were some header files which needed to be
    included in a few of the sources. A couple of if-then statements had
    assignments in the conditional part. The compiler warned that they
    should have extra "()"s around them. Made the code check the values
    instead.
Platforms tested:
    Linux (parallel) Modi4 (parallel)