hdf5_ep

[svn-r19683] Bug 2054: Round Robin code caused H5FFlush to corrupt a file.

John Mainzer fixed the bug and added a test which wrote file and flush a few
time; close the file then open it by serial and read simple structure. I
changed the test to two parallel running parts of ..._writer and ..._reader
and have the reader verify the file after every flush by the writer.

Tested: parallel in Jam and Amani.